Fair play. Lot or respect for people who keep their phones on silent. Too many people think they have to be contactable 24/7 nowadays, which is of course complete nonsense. If something terrible happens to someone you know you probably won’t get there in time anyway…and besides, you can regularly check for missed calls and messages without being a public pest.
To answer your question, all of them. 100%. If it’s work i’ll ring them back out of earshot of people i might annoy. If it’s social i’ll text back, again usually go out of the room if i’ve got company, though, as to not come across as an ignorant cunt.