Carry-ons (Opinions?)

Here's a question for discussion;
What's your opinion on carry-ons.
I travel for business, and check my tools & suitcase. I carry on my
Computer Case. I can't believe the amount of things that people try to
stuff into the overheads. If I put my case under the seat, I have to sit
with my legs in my chest. It goes up. I'll move it in an unusual
circumstance, but not for the half dozen people toting 2 or 3 fairly large
bags. And no matter what people think, the Airlines DON'T enforce the 1 bag
rule.