The construction worker's final line, "I'm feelin' mighty low.", was the catchphrase of the late Candy Candido, a famous radio personality and musician.
When Bugs falls into the rain water barrel and regains his senses after taking an I-beam to the head, he laments that "This isn't Saturday night." Bugs is referring to the common practice of rural and farm people of taking one bath a week, usually on Saturday night, so they can be clean for church the next day.
Original (rejected) title: "Blueprint Bunny".
Eastern Onion=Western Union.