Of course, it will make watching the game more exciting as you have a side bet, and you are going to cheer for your team, same as your friend. So there is this competitive fire between you two. But at the end of the day, it's just sports, and whoever losses the game will just treat it like that and nothing personal and you can go on and still be friends after it.
And I think this is a common occurrence when you go and watch with your friends in live games. Your bet, your drink and have some fun during that game. Of course, there will be some teasing on both parties, but you shouldn't look at it as personal attack.