Motivation has way too big an effect I think

If you start a game and a few of your players happen to be "Playing nervously", your performance is always going to be a disgrace.

I never understand why they are nervous either. They are treble winning veterans. Why are they nervous about some bog standard league game? I could understand complacent to some extent.

But yeah, the effects are ridiculous. One game I am bossing it, the next one they are a bit nervous so they all decide to play 10x worse.

You may have heaped the pressure on them during a press conference. Claiming it'll be an easy victory. That's how upsets happen.

Be all means be confident, but never expect to trounce the opposition.

lol Sheva... have you not figured it out yet?

What you SAY and what you DO, as well as what others say and do has an effect on your players... it doesn't matter if you've just trounced some lowly whipping boys 6-0 at home if the next game is against a fellow title/Europe contender at their patch and you demand a victory or whatever.. (analogy, I have no idea of the circs surrounding your latest whine)

Approach each game as a new game, forget what went before.. now it's about how you're going to win the next game. Check the odds, check their form, check their table position, their squad injury/morale/fitness status, the manager's opinion of you, their last results, etc etc etc... then use that info to decide what you're going to say in the PC, in the pre-match team-talk, in any private chats that you might have (or feel the need to have), are you going to praise the next manager or target a dangerman? etc etc

all is relevant, and will all have an effect on your team's performance... it's pointless expecting wins in close games and relaxing players to complacency in the supposed easy games, you have to get the balance right or it all goes Pete Tong

Edit:

Btw, I occasionally have players who are "playing nervously", sometimes even the majority of the team, but I can usually ensure that the performance is not a disgrace..