It probably has to do more of the mental aspect when it comes to gambling and being competitive in general. The more effort you give and strategize to a game, the more you will be affected when you lose. In your case, you get to enjoy your winnings because its either unexpected or you didn't really spend effort or time to make a precise decision on who to bet on. In result, your unexpected winnings would seem effortless for you and you feel more lucky than normal.
Even the strategies don't play out more than ones. A gambler might develop a strategy and gets lucky with it the first time and if the gamer decides to try the same strategy again on a different game he losses out straight. It's still safer not to take gambling as an occupation so that if by chance luck shines on an individual he goes home rejoicing else he wouldn't be affect psychologically because losses in gambling can trigger emotional trauma