I don't know that it has much to do with my Ohio State fandom. I grew up in Michigan, still live here, and basically root for all their college teams to do well other than their big one. I did root for Michigan against Alabama though. The Pistons are my favorite NBA team. I never really even had any animosity towards the Lions, their fans here have just been really irritating the past two seasons. I remember the Millen years, I get why they're excited, but damn the vast majority of the Lions fans I'm running into talk like this is some dynasty. At least try to have some humility.
I do agree with what you said about greatness. I feel like I missed out on really getting to appreciate Tom Brady and Tiger Woods because I rooted against them very hard at their peaks when I was annoyed with their overexposure. With Brady in his SB win with the Bucs and Tiger at the 2019 Masters, I finally got to enjoy watching them and was like "why did I hate this guy so much?". I hated Lebron at first too, but at least with him, I did start watching and cheering for him during his prime because I sympathized strongly when he got all that ridiculous backlash for "The Decision".