Out of interest, why do we board on the left and not the right? I think I'm right in saying that the whole world tends to board through the left or port side, why did it come to this?
This all goes back long before airbridges and pushbacks, to the days when aircraft approached the terminal, made a U-turn in front of it, stopped for the steps to be pushed up, and then when ready to depart just carried on round. Yes I know some airports are still like this (London City for one)
And as the captain sits on the left, the aircraft would be swung round "clockwise" rather than the other way round so the captain can judge clearance from things, particularly wingtip clearance that you couldn't see from the opposite seat.
Why does the captain sit on the left ? Well the main controls like throttles etc are in the centre of the aircraft, and as most people are right handed they will sit on the left of them, to use their right hands.
And if the pax are boarding on the left you put the baggage doors on the opposite side, so the trucks do not interfere with the steps or the jetway.