Preston manager Graham Westley emerged from a lengthy dressing room inquest after the 2-1 defeat at Yeovil and forecast tough days ahead for his new charges.
Defender Chris Morgan was dismissed in the third minute for a professional foul before Andrew Williams struck either side of half-time to put Yeovil in control. Clarke Carlisle headed Preston back into it with 16 minutes to go but Yeovil held on despite Paul Huntington seeing red for serious foul play in the dying minutes.
Westley, still looking for his first victory after three games in charge, said: "It is too easy to look for excuses in life and when we went down to 10 men in the first half we put in a performance that did nothing to lift us."
He added: "It was only in the second half that we showed any sense of urgency. For too long in the game we played with an excuse culture and I don't do excuse cultures.
"This football club has been on the back foot. They took 16 points in 13 games before I came here and when you are losing games and not winning points it happens for a reason.
"It happens because fitness is not right. It happens because the mentality is not right and if you have got people who want to take excuses into games you are not going to win anything.
"There is a big shake-up needed. We knew that before the game and the process is in place and people are going to need to shape up or ship out."
Yeovil boss Gary Johnson will appeal against the Huntington red card, stating the replays will confirm his belief the tackle was not worthy of dismissal.
The former Bristol City and Northampton manager, back after six years for his second spell in charge, saw his team record their second successive home win to move out of the relegation zone.
Johnson said: "We will definitely appeal. I have asked the referee to have a look at it. He said he will but thought it was an aggressive tackle. I thought that was the idea of a tackle - you go in to win the ball. I hope the DVD will show it was a very good challenge."