Ideally, you’d always like for your favorite team to be really good. It’s not the end of the world if they’re pretty bad, though.
Think about it this way: if your team is always good, you don’t have anything to worry about. Whether it’s consistently competing for championships or steadfast quality with occasional shots at greatness, it’s nice to consistently win more than you lose.
On the other hand, it’s not the worst thing if your team is... well, the worst thing. Sports are sort of like real-life video games — if you fail too much, you can always start over (though, admittedly, without a completely clean slate).