The hi/pretty good thing sounds very odd. If I overheard that, I would think it went like this:" high?"
" Pretty good!" (this Maui wowie is terrific shit).
Why would your choir teacher say “I can’t hear” when he means, “none of you can listen, you’re talking too much/too loudly”?
My bugaboo is “I feel ya.” NO, you don’t, ace. Back off and go away.
I learned “well, bless your (his/her/their) heart” years ago, and I’ve never used it in a genuinely well meaning way. It usually means, “well aren’t you stupid, but I suppose you meant well.” I’ll also say “bless his/her heart” when I hear kids screaming their bloody heads off and the parents aren’t doing anything about it.
A part of the “Uh huh” type responses to thanking may be born out of the excessive, employer-enforced thanking. I try not to do it, but it comes out sometimes when I’m being thanked for something that was not, in fact, a personal favor to the speaker or even slight inconvenience to myself. (Like at the grocery store. I got my food, you got your money. We’re square.) When it’s genuine, that “You’re Welcome” just comes out naturally, but when it’s fake/used a rote greeting, I tend to stumble (Or respond with “Have a nice day,” or something else more appropriate for the actual situation.