Turn up and go tonto at the first miss placed pass. Spread negativity and fear amongst a squad and make safe, shit, risk averse passes more likely?
If we are going to take the credit for driving the team on to superhuman efforts against Leipzig etc then you need to accept that howling in rage the first inkling that things aren't going you way, also impacts on the team.
The team don't win or lose because if the fans, but it influences it. And it doesn't help. Too many serial losers in the stands as well as the park.