At the end of your flight, don't wait until the line starts moving to get off the plane to get your bag from the overhead locker thus blocking everyone
Hmmm, I don't know about that one.
I'd say, ok, but don't start protesting either if you have to wait a few more seconds to get off the plane, because someone is taking his bag out of the locker.
It's not always possible to do so before the line actually starts moving. Specially if you are sitting in the window seat, you might be unable to even reach the locker before the other people have moved out of the row.
If you have luggage you should wait till everyone else without luggage is clear before blocking the aisles. This especially annoys me when you see people who have blatantly disregarded the carry on rules, and who insist on unpacking the overheads whilst everyone without luggage is standing behind them.
The reason people didn't take massive amounts of luggage on board was so they could move freely through the loading/unloading process. If you needed to stow stuff why should everyone else who didn't have to wait just because you decided to take a handbag, a baby, a carry on, a backpack and your vanity case etc? Sit down and wait - it's the least you can do after bringing all that extra luggage on board.
Rule of thumb: If you can get your stuff without holding up the queue, go for it. Otherwise sit down and wait.