This one's gonna Tickle

What is a Tickle? Why do we get tickled? Rather, how is it that some people just wont get tickled, my father for instance.
And why does a tickle make us laugh? and if does, is it that its a funny thing? and if it is a funny thing, why don’t we like it?
okay thats too many questions

not really sure, but:

some sort of nerve stimulation, i think. some people might have a slightly different arrngement/placement of those nerves.

The Master speaks.