If you have been gambling for long, I mean for a veteran gambler no amount of winning streaks could get into his head because he has seen and had many experiences with the act. He just accepts the winning streaks as they come in, knowing well that after a win comes some losses too. Gamblers that are mostly carried away are the newbie gamblers who haven't undergone through some of these experiences, as a result they get easily carried away.
Greed can make many things of you, but we should stay in control in order to continue to have fun and not harm ourselves in the long run.
Cold head in any situation, win or loss => a good time spent in the foreseeable future.
And I agree - we can't win forever. And we can't have bad days forever too.