Being sentimental about a particular sports team or your favorite player is okay, but to get so passionate that you place bets based on who is your preferred choice of team or player is being sheer silly. Betting on your favorite team or player even though the odds are clearly against them is not a good choice. The key here is to be sensible and calculate and bet on who the odds are towards, even if it means betting against your choice of team or player. A good better needs to concentrate on the outcome of the game and placing money accordingly and not only based on personal choices.
If there is a game that seems worth betting on, but you don’t seem to know the game too well, never ever invest in such a bet, it is bound to fail. The key to winning a bet is to develop the ability to see what a common person is not able to. It is commonly seen that a high profile match or game is often heavily bet upon. But a good better will often steer away from a bet that is already heavily bet upon but will rather concentrate on probably smaller games that he knows inside out. In such bets, the odds of winning as well as the profit percentage increases many folds.
When you get into the details of calculations and create complex spreadsheets, and forget to check the odds of each game you actually reduce your chances of winning a bet. It is important to look at the bigger picture, which in this case is the game in question.