Why is it that when you tickle yourself you don't laugh but when someone else tickles you you laugh?

No one is really sure, but we suspect it has something to do with your brain being subconsciously ready. Also you do not have the element of suprise so you're body will not react the samewhere as if another person weretickling you, you wouldn't have any idea of way they will tickle you and will cause you're boy to react by laughing, because they have the element of surprise to you.