I couldn't agree more! I once made the mistake of betting on a sport that I knew absolutely nothing about. I thought I was feeling lucky that day, so I decided to take a chance. Well, let's just say that luck wasn't on my side that day. I ended up losing a significant amount, and it was a tough lesson to learn.
That experience taught me to never bet on anything unless I knew what I was doing. It's not worth betting on a sport if you don't know the rules, strategies, and players involved. The same goes for making any kind of wager, if you don't know who or what you're betting on, then there's no way it can end well!
As long as that was a one-time thing then I do not really see anything wrong with that, after all we are talking about gambling here, a hobby in which we take risks just to have a good time.
But I do agree that when it comes to sports betting it is better for you to do so in a sport you know very well, or that at least you like to watch, this way you can significantly increase the fun you get when watching the different matches, as now you are watching your favorite sport not only because you like it but now you have something at stake, increasing your fun manyfold.