Carol,
Although this question was not specifically addressed to me, and, as a gentleman, I rarely brag about the impressive size of my carry-on, I will tell you in all honesty, mine is a hefty, but still regulation size, 22x13x9 inches, which is one inch less than what is published as allowable.
These are real inches - I just measured - not FF inches, which, unlike man inches, are actually smaller than reality. (Let's hope the neighbors weren't watching through the windows!) I also looked my bag up on
http://www.atlantaluggage.com and it agrees with those dimensions.
Despite my seemingly being within regulation size, my bag does not fit into the sizer, but does fit into the overhead.
I sometimes hear, "It's too big" or "There is no way that's going to fit in here" or "It will be uncomfortable for the other passsengers" yet somehow it always turns out to be an enjoyable trip for all involved. Of course, there are some FAs who look at the size of that thing and seemed to get excited about the challenge. They're the ones who work hard to make it fit, putting it in the other place (the closet) if the overheads are already too full.
What appeared to be too big is easily handled and it's usually a good ride for everyone. I've never had complaints afterwards that it took up too much room or caused distress to anyone.
Well, I'm off to take a shower now.