Your favorite team is screwing you.
Even if you don't care for the local team, or the sport, as a taxpayer you're saddled with financing a (supposedly) private empire. Most stadiums are constructed and renovated with public funds and, if your city government won't whore itself out for a retractable roof stadium, your favorite team will skip town. Why? So the owners aren't hassled with the upkeep of their own personal money printing factories.
Bottom line, you pay $30 to park in a stadium lot you helped finance, $250 for an officially licensed jersey, and, like, $7.50 for nachos. Go team!