Because I was so slow that I was tired seeing everyone finish before me.
Long jump because measuring my leap often caused laughter.
High jump surprisingly was not as awful and pole vault scare the crap out of me every time. I knew those metal poles were going to gore me or that I was going to miss the pit. I actually once vaulted into a sawdust pit. Scary.
Never got to toss anything other than shot put and discuss both of which were laughable. Coaches didn't trust us with the javelin.
So in truth, if it wasn't mile or longer, it was a fruitless endeavor.