You need to understand, mate, that if it’s your own money, then you should be the one responsible for how to use it and where to use it. There are two main reasons for the above advice. First of all, it won’t make you unsatisfied if you don’t win the bet, and secondly, you will do better analysis of the game before placing the bet. It’s better to place a bet on self-predictions and lose money than to bet on other people’s predictions and lose money.
You are right, most especially with the last part of your comment, that made me remember how horrible and cheated on I always feel when ever I bet on someone else's predictions and lost, I always feel very angry with the person who did that prediction and myself for believing in the prediction to the point of commiting my hard earned money.
So, indeed, you are right, it's always much better for someone to bet on his or her own prediction, and lose the bet, than betting on someone else's prediction and losing, atleast, with this, the gambler have no one else to blame and get agry at, other than him or herself.