If you lost you respect the winner and let him do the Ultra or whatever the hell he feels to do, because he earned it.
Perfect example at 54:09:
You can think about your mistakes or just enjoy the combo/fatality/babality/whatever meanwhile. Quitting before a match fully ended is a very childish attitude, no excuse. Be a man for your losses and your wins, but if you don't want to behave like that, go play other game suitable for your mindset and let the grown ups play.
The problem today is that the old values has been lost because of massification. If you RQed in the arcades back in the day, walking away from the machine before losing, the message you were sending was definitely not good, you know.
PS: "You", aka. anyone feeling identified with this behavior