You’re switching sports teams
It’s tough enough for Dad to accept that his NY-raised kid will never root for his ancestral Celtics, so a late-in-life, full-on sports team conversion could break the man’s heart, and warrants a sit-down confession. Maybe you got married and need to keep the peace, or perhaps you gave in to local pride when you moved out. No matter the reason, it’s probably best to have this conversation when Dad’s team (no longer your team) is doing well.
You’re having a kid
If your previous exploits have prepared Dad for the worst of drinking conversations, giving him good news -- like the fact he’s going to be a grandpa -- will be extra sweet. And Dad can help you manage the freakout that you will inevitably have next. Just remember, he did it, so you can too, right? ...Right?