English Learners: come and clarify your doubts

If you mean question tags like "aren't they" at the end of the following sentence; "They are good, aren't they?" Depending on how one says it, or writes it, the feeling can be sarcastic or not. David Bosch used question tags when he wrote here, and he did not mean to saound sarcastic or mean, but that is how he came across to me in his writing.

The British do not use question tags realy, except for "isn't it?" For example, "it's hot today, isn't it?" And I know the Americans do not really use questions tags. And we use "isn't," but not as liberally as the British.

Thank you, Chantal and Clark.
So we're taught sarcastic phrases at school without knowing it.
I learnt question tags as something causual!
Well, OK let's be careful when using them.
Apparently, the Americans hardly use them and I guess it's true the British use "isn't it" only, that's what I heard when chatting with some of them.