Soccer: What/how to watch? Who to root for?

So I've recently decided I want to start getting into the most popular sport everywhere except the US. However there's so many leagues and teams, I don't know which to watch and who to root for. Should I watch EPL? La Liga? Serie A? MLS? All 4 or more? None of those? Also how to I decide on a team to root for since I have 0 connection to any of the teams outside of the MLS? Also, one last question, what channels to these games come on. ESPN doesn't usually show them as far as I know, so any help is great!