[jimmytheg]

depends on limit or no limit....in limit there are many times when you have to call a river bet even if you are sure you will lose 9 times out of 10,if you are getting more than 10 to 1 on your money

in no limit, there are many instances where you can be pot committed preflop, especially late in a tournament with a short stack.Late in a tourney if you make a raise for around 75% of your stack, you are gonna have to call a reraise with basically anything. Im talking when the blinds and antes will eat you up in a round or two if you fold.