Nuances of вообще-то vs на самом деле

Question

I understand that both на самом деле and вообще-то are used to correct a misconception or present a clarification of the reality of a situation. However are they completely interchangeable, or (as a native Russian informed me) can вообще-то express some frustration or even anger on the part of the speaker?

For example, if someone offers you a cigarette in a social setting, it's quite polite to say "Actually, I don't smoke." (with a smile, of course). However, my friend told me that saying "Вообще-то я не курю." would sound defensive and reactionary in Russian. He cited the following exchange:

Слушай, у тебя такой кашель.... и ты бледный какой-то... Может тебе пора бросить курить?

— Ага, спасибо тебе! Вообще-то я не курю.

Answer 1

he's right, вообще-то said in response implies that the interlocutor should have known their statement was inappropriate or wrong or stupid, so as to contradict their expectations, but it of course can be expressed both aggressively and amiably

in the example вообще-то can be replaced with на самом деле without loss of meaning if the original phrase isn't meant to express strong emotion

generally на самом деле doesn't have these strong connotations of вообще-то

Answer 2

They all mean "generally", however вообще-то is more colloquial , на самом деле is more neutral.