Concerning a monkey and a football....

I consider myself fairly mechanically handy. I have changed starters, alternators, tires, assorted filters and hoses when needed. It is nice to have a man to do it, but I don't need one. However, I have never before changed the tube in a bike tire. Of course there are no instructions. How hard can it be? Kids do it. I double check the size, yep right one, then why is there like 3" extra? And how the heck do you get it in there? Are ya supposed to take the whole tire off or just kinda cram it in? I did prevail over the damn thing, With the help of a wrench,my technique may not have been perfect, but the tube was all in there, and it held air, did not explode or anything and I celebrated by riding the boys bike around the block a few times, just to prove I was the damn boss.
Now my thumb hurts. Don't ask.