i prefer on sports that I know and follow. I will not put up without having knowledge of the team because it usually makes losing money
That's true...
Too many factors can effect a game, for example the starting eleven (in soccer),
if you bet on something you don't really know, you won't know about what is their normally stating players,
and why the normally stating players are not started this game, maybe injuries, suspended...
So better to bet on the games that you know...more chance to win money.