It must be a personal thing then. I could say that 10 years ago with Tyrone, Arsenal and whoever else it affected me. Whether it was fatherhood, wising up or realising these fcukers are earning millions and don't really give a shit (not Tyrone I think), I'm only annoyed for about 5 minutes before re-focusing on more important things.
Not just you. I'd imagine it happens to most.
I thoroughly enjoy when Liverpool play well and win, and I enjoy reading about it and watching the highlights of the games again while exercising and so on. I get frustrated as f**k watching them when they're shite, but the minute its over, I shrug it off. If Liverpool f**king up is the worst thing to happen to me that week, it'll have been a very good week. Basically, its a hobby to be either savoured or forgotten about, depending on how it goes. Its not real life.
I'd have a similar enough attitude to the Donegal county team as well, although there is obviously more of a personal connection when you come from and, in some cases, know the people involved (or at least their families).