I have news for you, lady. You are a menace.
First of all, why on EARTH do you need that much crap? Second, even if for some reason it turns out that you do need 400 more items than anyone else during the work day, why the HELL can't you consolidate it? Third, and listen closely now: do you think you are the only person on the train/bus/cable car during rush hour? Do you REALLY think that because you are you, that other people who only need a normal amount of crap with them or know how to consolidate it should give up their seat because you are disrespectful and possibly a little bit crazy?
If you need to have with you the amount of stuff that would fill a minivan, here's a tip: DRIVE TO WORK.
We live in a city where space is at a premium. You don't have the right to more than your fair share. And you insult me when you try to catch my eye on the train to make me feel guilty for sitting. Um, hello? I can keep my crap from hitting every third person I walk by.
Also? Your purses are hideous, that canvas tote smells funny, and no one under 50 carries actual briefcases anymore. Get a damn clue.
I'll gladly give my seat to a pregnant woman or someone older or disabled. But at you I will just scowl and then go back to enjoying my comfy ride.