I had no good reason to love the Oilers, but I did/do.
I've become a real Philadelphia Eagles fan because my 18 year-old son is a fan. Watching them lose and watching my son meltdown (sometimes violently) after each loss made me very emotionally invested in them. I'd normally prefer BYU to lose than Philadelphia. I can shrug off a BYU loss. It's not so easy to watch my son when he throws a fit. We've been afraid for our safety. It's one of the reasons he no longer lives with me full time.
I cheer for the Patriots because my 21 and 10 year-old sons are fans.