Bluepilot has it right - when you are a First Officer you think all the dorks are in the left seat but when you become a captain then you realise there are one or two guys in the right seat who are not too great either!
Regarding 280kts in a procedure - a potential disaster awaits. In my last company we had a captain who not once but twice did that and both times it resulted in hard GPWS warnings near high ground. On the first occasion it also nearly resulted in disaster as the captain got stuck in Alpha Floor/Toga Lock and could not get out of it (if you are not on the Airbus just ignore this bit!). He was given retraining in the sim and then did the same thing again some months later! He was given the choice of becoming a First Officer or leaving and he chose to leave. He is now on a 737 with a company that has a less than perfect safety record! This guy had a long history of being a nightmare to fly with and taking unprofessional decisions. The moral of the story is that if the guy next to you is being stupid you tell him! It is so easy to say that but the bottom line is you have a higher responsibility to your passengers than you do to your own comfort. That is definitely a case for expressing your concern on the ground afterwards. If you get no satisfaction then you should take it to higher authority.