I may be off base, but when I was drinking and for years, I had no caution or censor, and this was also a coping mechanism for anxiety. To bulldoze all decorum into clown status. And now that I am sober and older, I am very cautious about my speech, but there are also lingering resentments cultivated through years of not knowing what genuineness was, and I think being around people with a similar problem who also didn't really prioritize that. Where there is risk and fear, there are defense mechanisms. 'Have a nice day!' and other Americana is heavily loaded with salesmanship, and I think it's natural to read a kind of double entendre onto it. And yet it's often just the style.