Been to most grounds in North Wales to see Cymru Premier games.
In Europe I have been to Barca v Espanyol, Real Madrid V Sevilla and AC Milan V Empoli (possibly the worst game I have watched).
When in the US I went to see Seattle V Minnesota Unite, that was good fun. I overhead one woman saying to her friend that she only comes to watch the second half as nothing interesting happens in the first half. They had these really cringe worthy 'super fans' with loud speakers who stand on plinths singing awful songs to get the crowd going.