I don't see any reason why should get their hope high in gambling, when you are fully aware they you winning is boils down to luck . Which means you can either win or lose . So not getting your expectation high would help in relieving the stress in gambling. And would help one to approach gambling in the right way , because most time alot folks always get their hope high in gambling because they believe they can get rich through gambling fast which may also trigger some sense of gambling addition too.
I personally don't see any reason why someone should procrastinate on something that is yet to come and even worse, something that's based solely on luck. Gambling is either you win or you lose most of the time and that makes it more like a 50/ 50 event a majority of the time. It's like expecting money you are not 100% certain is coming and that in fact is bad planning.
Infact overestimating your winnings isn't good for your emotions. That's because if you eventually end up losing the bet you would feel the hit more intense than when you accepted it that there is a possibility you could actually end up losing the bet.