I also travel extensively for work on week or two week long trips with a half size carry on that gets checked if I can take two bags and goes in the overhead if the airline is one that charges for a second checked bag, my lap top goes under the seat and I check my suit bag. If I have files, or other bulky items that have to go, I ship them in advance via fed ex or UPS.
It bothers me when people walk on with an enormous carry on that really should have been checked and then a large "personal" bag that they put in the overhead bin rather than under the seat in front of them. I really despise the overage hippies with backpacks that barely fit lenghtwise in an overhead bin - if it is over size it should be checked, backpack or not.
Some business travelers are just as bad however when they save 20 minutes waiting for baggage by taking a large carry on without checking anything. Personally, I think the cabin is safer in a crash or heavy turbulence with fewer bags in the cabin.
Charges for a second bag just makes it worse as travelers just bring it on board rather than checking it and the aircraft still takes off with the same weight on board.
I am also one of those guys who will pull the bag out of "my" overhead bin if a passenger 10 rows down decides they need to stuff it somewhere other than their own bin. In return if my considerately small carry on will not fit in my bin or one adjacent to it, I ask the flight attendent to stow it or put it in the hold.
While we are ranting, why do passengers with multi hour lay overs or who will have to wait 20 minutes at the baggage claim anyway insist on getting up and blocking the isle and delaying passengers with short connections who really have to hustle to make a connection if the flight is delayed at all. Some flight attendents request that people with generous layovers please wait to deplane, especially when the flight is behind schedule while others do not, but it really makes little difference as passengers seem to be obsessed with getting off in order from front to back whether they have anywhere to go or not.
And...why do airlines board in zones running from the aft of the cabin forward rather than boarding window seats, then middle and then isle seats (with suitable exceptions for couples parents and kids, etc.) The zone combined with murphies law ensures the people in the isle and middle seat will be ahead of you and will have to get right back up to let you into a window seat.
I won't even get into overbooking or cancelations...