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".
The postwar construction boom was in full swing at the time of this short, with everything from suburban housing to new urban high rises being put up in large numbers.