Crystal Palace manager Neil Warnock says he has been told his side should appeal more for penalties, describing his players as "too honest".
Palace lost 3-1 at home to Sunderland on Monday, extending their run without a Premier League win to four games.
Warnock's side had a strong claim for a penalty denied inside the first minute against the Black Cats, when Santiago Vergini brought down Fraizer Campbell.
"I was told we should appeal for penalties a lot more," said Warnock.
"But I don't understand why we should have to appeal. If someone kicks your shin, they should be given."
Steven Fletcher scored twice at Selhurst Park as the Black Cats lifted themselves out of the relegation zone.
Wes Brown's own goal cancelled out Fletcher's first goal, before Jordi Gomez re-established Sunderland's lead and Fletcher sealed the win.
Warnock was left to rue Phil Dowd's refusal to award his side an early penalty, one of a number of decisions the Palace boss feels have gone against his side in recent games.
He also questioned what he called an "assault" on his goalkeeper Julian Speroni during a 2-2 draw at West Brom.
"To say we are not getting decisions is an understatement," Warnock said.
"There are too many mistakes. You have to give penalties, you have to be brave to give penalties and they don't seem to be doing that at the moment."
Warnock feels his side may need to develop a nasty streak, adding: "I think we're too nice at the moment. We are too honest."
Defeat means Palace drop to 17th in the table, outside the relegation zone only on goals scored.
They head to Manchester United on Saturday without captain Mile Jedinak, who was sent off for a second booking late for kicking out at Gomez in the centre of the pitch.
"He has apologised and has let the lads down in that respect," said Warnock.
"We have got to go to Old Trafford without him now for something as silly as that."