I say thank you and keep going. Antiquated or not, at it's core, they are showing concern for your continued wellbeing. And, since they are utterly helpless to truly affect that sort of thing, they do what's available to them and ask their alleged higher power to bless you with health, which is actually sort of sweet in a naive sort of way.

I've seen people interrupt all kinds of significant goings-on, just to do the damn "bless you" thing ! Like if they don't , something truly awful will happen !
So incredibly mindless. Programmed robots.

I think it’s a little silly to be bothered, it’s a cultural habit. I usually say salute but that’s my Brooklyn Italian upbringing. If someone agrees with you by saying “Damn straight” is that a problem?... or when something is a surprise I like, “jumping Jesus!” .. I get pissed when religious people go to areas high in aids and tell people condoms are sin... I don’t have time to be mad about linguistic habits that amount to nothing more than being polite.

I sneeze-bless u I can handle. LOL

I actually appreciate the goodwill gesture.

I pay little attention. Besides, I've been living in Thailand since 2010 and nobody says that here.

how do you feel when a man orgasms and says fucking Jesus im coming?

I don't think about it.

I ignore them.

The Germ term is better.. "Gesundheid" meaning good health