Don't worry, I still don't have a favourite team. I guess it's hard since it's not like supporting your home city/state's team.
I tend to like teams that build through draft and like them then I don't like them once the team changes direction. Look at say Heat with young Wade, Odom & Butler. I loved that team. Then they traded for Shaq & their team's playing style changed, so I didn't like them anymore. Same with mid 90's Lakers, fun team to watch. Then they sign young Shaq, trade Ced Ceballos & they are no longer enjoyable to watch (except for Eddie of course). I liked Knicks with Lee & the other young guys, but then they ditched all them to get Amar'e & Melo, so they suck now.
I've just come to the realisation that I'll never have a favourite team

Coaches, front offices & players change too much.
But if I had to give you a suggestion of who to follow, pick a young team with a good young player that you like who will be with the team for forseeable future:
- LA Clippers: Blake Griffin (too late, bandwagon has passed)
- OKC: Kevin Durant & Russell Westbrook
- Washington: John Wall
Alternatively be more savvy & pick teams with likeable pieces:
- Denver: Nice young guys like Ty Lawson, Arron Afflalo, Wilson Chandler (once he resigns) plus likeable vet in Nene & super likeable rookie Kenneth Faried
- Minnesota: Love, rookies Derrick Williams & Ricky Rubio plus everybody loves Darko
Or you could be patriotic:
- Milwaukee: They've got Andrew Bogut, the one armed Aussie. Although you'll pray they send Brandon Jennings away to oblivion
Or you could use choose a team based on who you used in dynasty/association modes like I have in the past