wow, very bad tactic in my opinion (the way you're doing it). If you raise them on the river, you have nothing and then they RE-raise you, they're going to have you beat in most cases. In situations such as these, where someones been betting aggresively all night, it's still not worth it! They might have a tiny pair which would still bet you're high card! Sometimes in poker, it is the hands you let go, even when you're priced in that allow you to win or save money.