This has probably been said before but the one thing I notice and see frequently is when one of my friends appears to support me during a game, especially if they are within that 15% threshold, it can affect the variable of the game and more often than not it can have a detrimental effect. Usually the opponent scores against me? I've seen this when I log into one of my friends' game as well, often a goal is scored against them.
Maybe I'm at the point where supporters are a bad omen !
FC Loella. Server 121. Level 23
14 League Titles
3 Champions Leagues
1 Cup