Dude--relax a little before you blow someting.
I don't know where YOU fly, but I've never heard the "we're not at the gate" PA other than when we're stopped. It certainly isn't made while maneuvering to "avoid moving ground equipment." Passengers can generally see they're still moving. It's after you've been taxiing for a while, and then you stop--especially when you can see out the window that you're near the terminal--that passengers might not know any better and start to unbuckle and get up. That's when pilots generally make that PA--with the plane stopped, and presumedly the brake set.
As far as your other complaints, at my airline, the pilot preboard PA and the F/A reward points PA are listed by the company to do as time permits. I suppose you can say F-you to the company and blow them off--obviously some people do--but for some funny reason, some crew members try to do their jobs as the company asks. As far as "turn off your cellphones" PA, the FAA requires the crew to pursue this. If a passenger is doing something illegal, and an FAA inspector sees this and can see that a F/A notices but doesn't address it, than the F/A can get written up. it's up to the F/A whether to use the PA or go up and get in a specific passenger's face personally, and I suppose it's up to them how to address it. Some do it differently.
Coke vs. Pepsi? I've personally never heard this, but I suppose if you've had to tell a passenger the the 90th time in a row that hour that you don't have Coke, you have Pepsi, you might be tempted to make that PA to cut down on order time while you're working. I've never been a F/A, but I can imagine.
You probably shouldn't fly so often if it bothers you this much. 'Cause that kind of stuff isn't going to change.
Bubba
