[skardan]

It is sad nobody mentions book The Humane Interface by Jeff Raskin.

Raskin would say, that this is not a question of red or green. It is a question of habit. If user deletes enough items, you will train him to press "Yes" button and not to think about the question. It will be his habit. Uninterruptible sequence.

Anybody deleted his important files just because he is "trained" to press sequence F8 - Enter in his favourite file manager?

Raskin recommends to provide undo. User content is sacred and should not be lost. You can also try to randomize the dialog. User will stop the sequence and think what he is doing. But if user performs the delete operation often, he will be greatly annoyed.

Read it. It is a great book with many valuable gems. http://amzn.com/0201379376

[ASneakyFox]

Please do not randomly change buttons. Thats the worst idea ever. Where does this guy do his research?

[lttlrck]

"Cancel"/"No" should be on the left (go back) and "OK"/"Yes" on the right (proceed).

(There may be guidelines that do the opposite and I guess RTL locales may reverse it).

Deliberately ignoring HMI guidelines and switching button placement is irritating and does not remove the muscle-memory (?) problem. Doing it randomly is nuts and leads to mistakes that are IMO not the users fault.

It you want to interrupt a sequence, there are kinder ways of doing it like double confirmation.