Well it's because of the sadistic payout system.
1st place = Prize
2nd place = a little won
3rd place = a little lost
4th place = fuck you
Mahjong was originally designed to be a cash game so it's not unusual for you to have this mentality. In riichi mahjong, it's tournament style, so scores are relative and you just want to have more than other people.
Of course you can bail less as east, since...
1.) You win 50% more as east.
2.) Dealing in costs the same
3.) You lose more when someone self-draws.
4.) You get to continue being east.
For example, take a look at this. I basically could have gotten third easily had I bailed on those 2 hands. Of course the player to my right was a douche, but that's a story for another day.
http://tenhou.net/0/?log=2013052816g...-013881fe&tw=2