I know it is always controversial when people say this but I strongly support 3 teams, and I'm a fan of many others.
I support Chelsea not because I wanted to, my dad and uncle were born not far from the Bridge and were season ticket holders back in the day. I was told I would be disowned if I didn't, and when you're 2 or 3, that hits hard lol. Starting to lose touch with Chelsea because I can't get tickets anymore, the stadium is dead at home games and away tickets are always sold out.
I support Lech Poznan in Poland, because my family lives there, and everyone supports them. Poznan is pretty much a one club city, and I always try to go when I'm around. Incredible atmosphere, even with attendances of 20,000.
I support Oxford United because this is my local team, my dad would take me when I was small because he didn't have the time or money to drive to London every weekend. My dad didn't really develop a passion for Oxford, but I go with my mates very often and I prefer the atmosphere of the Football League than the Prem, no glory hunters or tourists.
I also follow Oxford City (non-league), Dortmund, Fiorentina and a few others to stay interested in other leagues.