Sometimes when the door is held open for me, or someone moves to allow me to pass, I try to say thank you and no sound comes out! I don’t know if it’s a form of social anxiety as it only happens with people I don’t know.
I end up smiling like an idiot to make up for it!
Can a smile ever replace saying thank you or am I being really rude?!
I hate it when people are passive aggressive about manners. To me it's really rude! Manners are basically about making others feel comfortable so highlighting their bad manners highlights your own (hope that makes sense).
To answer the AIBU: as far as I'm concerned a thank you (or a please) can be, and often is, implied. And a smile is a good way to do that.