How come with TOS, symptoms are always delayed?

For instance, I'll do something on monday that I know I should not be doing and my pinkies will be numb on tuesday and wednesday.

Do that same thing again on Thursday and my pinkies will be numb on Friday and Saturday.

WHY the delay?

I have often thought of it as a bank account. You can do whatever you want (sometimes) but once you overdraft, then all the little things that you used to be able to afford, are now costing you.