I usually place my bets in the Spanish La Liga, not because of any special characteristic but simply because that's the league I know better (I follow it since I was a child), and I focus on enjoying my bets instead of other technical reasons that can be valuable for a more rational user.

The second League I bet most on is the EPL. Personally, I hardly ever bet on the Bundesliga, the Italian, French, etc. not to talk about other continents, except for really decisive or historical matches.