For example, you put yourself through university by studying hard and working full time. Then someone says, you should thank god for giving you the strength. Like wtf do you mean, I busted my ass day in and day out but I’m supposed to thank god for it?
This is the first time I translated “bless you”. I never knew it was something religious. In german we simply say “health” (Gesundheit) when someone sneezes.
Its a hold over from the plague I think, plus general religiousnous in the past. https://www.theguardian.com/lifeandstyle/2011/feb/14/why-do-we-say-bless-you-notes-queries