system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: European soccer leagues

I'm American, and played soccer as a kid, but I never paid attention. I've watched a few big Mens World Cup, and I like watching.

I want to start following a league, and Barclays Premiere League seems the most accessible. I've heard of Man U, Arsenal, Chelsea, Real Madrid, and Barcelona, but that's basically it. What leagues consistently have the best soccer to watch? Besides Premiere League, what are other leagues soccer fans typically follow?

Followup question: what random team should I adopt?
gpt
In a nutshell, every country has its own league, from the big boys like Spain and England to minnows like Moldova and Wales. The top teams from each league play each other in the Champions League every year, with the Europa League as a sort of second-tier Champions League for good teams that didn't quite do as well. 

The best advice is pick a league to start following (whatever's most on tv near you is a good idea) and pick a team. Do some research into the clubs and find one that represents you. Keep in mind as well that with promotion and relegation (imagine every year if the top AAA teams in baseball were promoted to the Majors and the worst MLB teams relegated to AAA), that if you pick a small club, they might not be around in the Premier League next year. 

Top clubs in England with long histories and likely to remain competitive for a long time are, in no order, Arsenal, Tottenham, Aston Villa, Everton, Liverpool, Man U, Man City and Chelsea. Some would add Newcastle United to that list as well though they're currently in a major period of instability. 

Don't pick Manchester United or you're a twat.