Toss of the coin

Common phrases used by most people in the game of " I am always right "

" Yes but ......... "  and " I told you so " or  " Didn't I tell you "

It works like this : You moot an idea to a group and the above immediately give you all the reasons why it can't work

You go ahead with the idea and it works they can claim that their observations helped you iron out the weak points and hence success but if it fails ..... Then they had said so hadn't they ? 

HEADS I WIN TAILS YOU LOSE !