Guild Wars 2

I started playing the game a month ago and easily leveled to the max level of 80 but i’m not sure what the goal is. I understand that I can scale down to lower zones, and do all the hearts/jumping puzzles/waypoints but that is very boring. Pvp is a 35 second suicide and the WvW is too confusing, is there anything else to GW2 ?

Every time I try and sell things at Black Lion Trading Company I get “Error Attempting To Sell”. How do I sell things in GW2 then?

I just started playing the game the other day and i am level 11. Where do i buy “skills and traits”?