what do you do when you're angry because you cannot think of clever replies to someone's comment

i at times get this problem online, someone answers my post disagreeing with or undermining my points...and i can't think of a clever response on the spur of the moment? and i feel so angry as i want to get the better of that person and comeback with clever replies....but my mind goes blank, and i see red mist with anger.

what can you do when you encounter this problem?