Gambling games are unpredictable, sports betting types are more influenced by luck. We must admit that in the world of gambling, nothing is certain. Everything in the gambling world is very difficult to predict. Never expect too much because basically gambling is a way to get pleasure. We will not benefit because the main thing is to get pleasure and it is not an advantage in the form of money.
Yes, it is difficult to predict. However, for example in sports betting, there are statistics with players performance, history etc which can give you some indicators on what you will play. You describe gambling like it is something random, but it isn't. Playing with the odds is what makes gambling addictive and people stop being prudent and lose money.
With good anticipation and if you really watching the type of games you bet with, you can take the advantage of your good knowledge regarding to any sports gambling that you are engaged, odds affects you since challenge is there with what you think will perform well against the tempting odds that you are seeing around.