It does bother me when people stand in the walk side of a moving sidewalk. You can even give them an "excuse me" and they just stand there making you go to the next step of "move it" or "coming through".
Also: The groups that MUST walk three and four abreast around the airport. You can be walking and there is no way they move or separate. I used to go around but now I just keep going straight in a little game of "concourse chicken". These are also the same people who have to walk/stroll/stand two abreast on the moving sidewalk.
It also bugs me that many airlines, with assigned seating, do cattle call boarding. They board first class, Elite passengers and special needs and then call the rest of the 34 rows for boarding. It's a mess. Calling the rear rows of the plane and then going forward is the most efficient. I compliment the gate people when they do this and I REALLY compliment them when they enforce it.
I have traveled "a lot" over the years and I put myself into a zone when I get on the plane and few things bother me. Percentage wise, I have had fairly few incidents. There have been the talkative folks who didn't know when to stop but most of them were just nervous about flying.
A couple of incidents of kids kicking the back of the seat but a request to stop has been honored.
The one person that comes to mind was a guy who was using his laptop on his tray table. I don't know if he was using his laptop or chopping meat. After about a half hour of being bumped and jostled I asked him to be a little more gentle with the seat. He continued excessively jostling the seat. So I finally just pushed the button and pushed the seat all the way back. He uttered a WTF and told me to push the seat forward. I said I would if he quit banging the seat. He agreed and I put the seat back up and all was well for the rest of the flight.
I have a pretty high tolerance for kids. Infants and young toddlers don't know what's going on and the air pressure hurts their ears so I know it's not their fault to cry. I also see the frustration on the faces of the parents.
The worst "smells" I have ever encountered on a plane have come from the galley. Some of the "breakfast sandwiches" that Northwest serves/served almost made me gag from the smell of the sausage. I'll take the smell of bacon and eggs, or a Whopper, any day.
I do believe that the more apprehensive someone is about flying the more "little things" bug them.