BOS-SEA is the worst. Everyone crowds the gate before the inbound SEA flight can even disembark. Several times I have lucked out and got the upgrade and have excused myself past 3/4's of the mob so I can board. Dirty looks from some, but oh well, sit your a$$ down until it's time to board.

Will be interesting to see if BOS-PDX is the same (I fly first time in July).