One of the quotes that randomly pops up when speaking to smug villagers, they state that the words/phrase "C'est magnifique!" is Spanish. It is actually French.
The emperor butterflies that are from the family of Nymphalidae are depicted to be nocturnal, being active from 5 PM until 8 AM. In real life, they are diurnal.
The players' flights to go to Mystery Islands, Harv's Island, and the Paradise Planning archipelago and back to the airport happen to do so in less than a minute. These flights could never have taken that short of time in doing so.
The Maple Leaf Season is depicted running from November 16th through the 25th in the Northern Hemisphere and May 16th through the 25th in the Southern Hemisphere late in the fall just shortly before the beginning of winter. In real life, leaves fall off of their trees in the middle of the fall season and that there would be minimal to none left on their trees just before the dates this particular season runs in the game in their own hemispheres.
The Yellow-Tile Roof out of the House Customization options for the player's house - despite the name, it's shingles are actually orange.
The villagers' legs clip through their own clothes when sitting down.
While the player can gift villagers articles of clothing where they may wear them for particular activities and hobbies: fishing, catching bugs, exercising, sleepwear and sickness, snowfall, etc.; if the player gifts a villager a raincoat or rain hat, they will always wear the ones they initially wear despite being gifted different colors or variations and will only wear the gifted ones while indoors or if the weather is anything but rainy, unless holding an umbrella.
Wall-mounted items often clip through other objects placed on the floor and/or ceiling depending on where they're placed, and that the player and/or villagers can clip through them.
When the player leaves any building, Tom Nook, Isabelle, and villagers of the lazy, normal, smug, snooty, and cranky personalities use the Greetings reaction rather than Wave Goodbye. The jock, peppy, and big sister villagers on the other hand however use the Double Wave reaction when the player leaves their houses that would be one of the more proper reactions for saying "goodbye".
In early versions of the game, if a campsite visitor was invited to the player's island and swaps out one of the current villagers living on the player's island after 10 housing plots are maxed out, the new villager after moving in would have his/her proper house interior but retain the same house exterior as the one whom moved out (eg. if Kabuki as a campsite visitor moved into the player's island in Dom's place, the former would have his proper interior but would have the latter's exterior instead). This was patched up in the 1.3.0 Free Summer Update (Wave 1).
Many fashion items added in the 2.0 Free Update when gifted to villagers will only be worn casually instead of via hobbies and activities. For instance, they will not wear an open track jacket while exercising (despite that it's similar in appearance to the athletic jacket they initially wear for such hobby/activity) or a loungewear shirt as sleepwear or when sick - despite their purposes.
The promotional artwork depicting the player house depicts it having Chic Cobblestones for siding and Blue Curved Shingles for roofing. When the player first gets the second story put onto his/her house, they initially have the Common Exterior for siding and one of the eight Tile Roofs based on the color last chosen for the expansion process after paying each loan to Tom Nook.
Due to the game's ability to time-travel, players can visit other players' islands not just by time zones, but based on the time and date settings on his or her Nintendo Switch; despite the game being intended to be played in real time. So, technically the Dodo Airlines seaplane acts more like a time machine than just simply traveling within or to different time zones.
The game runs through four seasons of the year, and that coconut trees can be planted on the sandy beach or on sand path tiles. Coconut trees that are tropical plants would never be able to survive during snowy weather or climates where snow can occur.
The Holiday Sweater can be purchased from Able Sisters during the Festive Season that runs December 15th through January 6th. Since December is in the winter in the Northern Hemisphere and summer in the Southern Hemisphere, nobody would wear a sweater during the hot summer days, especially considering the fact that the Northern and Southern Hemispheres are seasonally six months apart.
The Minicar furniture item uses a right-hand drive configuration like in Nintendo's native Japan and in Commonwealth English-speaking countries that use left-hand traffic, but the Luxury Car uses the left-hand drive configuration like in North America, most of Europe, and most countries in the world that use right-hand traffic.
In early versions of the game, the Imperial Series furniture items were erroneously referred to as the "Zen Series", despite being based upon Chinese culture that use the "Imperial" name of in the form of architectural designs and furnishings, while Zen refers to the Japanese form of architecture and furnishings. This was corrected in the 1.9.0 Free Update released in March 2021.
The hours of the hosts at the Open-Air Market on Harv's Island as depicted:
The day cycle begins at 5 AM each day and the shops are open anytime within the range of a day cycle beginning. The hosts of their respective booths in the Open-Air Market on Harv's Island would not have enough energy to go back to their duties.
- Tortimer's access to the player's storage and Leif's shop run until 11 PM
- Kick's Shoe Shop, Saharah's Co-Op, and Cyrus and Reese's furniture customization workshop run until midnight
- Redd's art shop and Katrina's fortune telling booth run until 1 AM
The day cycle begins at 5 AM each day and the shops are open anytime within the range of a day cycle beginning. The hosts of their respective booths in the Open-Air Market on Harv's Island would not have enough energy to go back to their duties.
While the outdoor lights normally turn on when the sun goes down and that villagers at home close the curtains to their windows when this happens, they all do so during periods of rain regardless of time of day, but not during snowfall before the sun goes down; even though snowfall is the winter equivalent of rain.
At Able Sisters, Mabel rings up the player's purchases, but there is no cash register present in the shop.
After completing the main storyline of the Happy Home Paradise DLC (30 vacation homes and opening up the Apparel Shop as well as holding the first ever DJ K.K. Concert) which gives the player the ability to talk to Tom Nook about remodeling villagers' houses or to ask Isabelle to reset the appearance of them inside and out - the former after doing the project doesn't become effective until the next day cycle after when the clock hits 5:00 AM, but the latter however opts to have the villager's house appearance reset on the same day within seconds of discussing with Isabelle about a villager.
Flick and C.J. as they each visit the player's islands stay up for the entire day cycle that begins at 5 AM. They would have never been able to stay up that many hours without getting exhausted as most other NPC visitors that can be present as early as 5 AM when a day cycle begins usually leave the player's island anytime between 10 PM - midnight.
When villagers comment on piano or synthesizer furniture in their own homes or while visiting the players' house, they state they are incapable of playing them. In "Happy Home Paradise", if the player drags the villager and places him or her in front of a piano or synthesizer, they are shown to actually play these instruments.
When villagers comment on food or kitchen appliances, they label themselves as being incapable of cooking. Yet, after the player obtains the ability to cook since the 2.0 Free Update and has Resident Services upgraded to a building, villagers are shown to cook when using kitchen-type furniture used for prepping.
Redd is a male, but he has the voice of a big sister villager personality intended for female villagers of said personality and some female special characters.
Chai, the Cinnamoroll-based villager has a peppy personality, making it a female; but the titular character of the Sanrio franchise it's based upon is a male.
Villagers of personalities that go to bed in the range from 11 PM and 1:30 AM and who wake up in the range of 6 AM and 8 PM initially wear terry-cloth nightcaps as sleepwear and when sick while those who go to bed in the range from 2 AM and 3:30 AM and wake up in the range of 7 AM and 9:30 AM don't initially wear terry-cloth nightcaps for sleepwear and when sick unless gifted by the player. This hardly makes sense which the terry-cloth nightcap should be more for those who wake up later in the morning when and/or after the shops Nook's Cranny and Able Sisters open at 8 AM and 9 AM respectively.