The Lions have now won just one game from their last seven and crashed back to earth after a morale boosting win over Collingwood in round 10.
Voss said costly 20-minute lapses, evidenced by a 34-point deficit at quarter time proved damaging and that the players may have developed a high opinion of themselves.
“Maybe there’s a thought that we think we’re better than what we actually are, and we come into games with that mentality as opposed to treating the game on its merits,” Voss said.
“There is an effort that is required over a complete game and at the moment we’re not meeting those effort levels.
“I think what we need to be able to do is start to challenge ourselves a little bit more and risk the chance of actually leading early and see what happens from there.”
To compound the loss, Simon Black faces a charge of abusive language against an umpire after being penalised for a throw in the dying minutes.
While replays showed it was a legitimate handball, Voss backed the AFL’s stance in protecting umpires.
“They’ve got a job to do and we’ve got to make sure that when the siren goes too that we also respect that,” Voss said.
“It was a hurtful loss for us, the guys were clearly hurt, clearly animated after the game.
“You could see certainly afterwards that the players were really disappointed in the fact we walked off with a loss.”
The Lions face the Western Bulldogs at Docklands on Sunday afternoon - their second meeting of the year after the Lions triumphed by 22 points at the Gabba in round four.
The Bulldogs sit in sixth place on the ladder while the Lions sit in 10th, but equal eighth on points tied with Hawthorn, Essendon, Port Adelaide and North Melbourne.
Voss said he rates the Bulldogs very highly despite the Lions' victory seven weeks ago which gave them four straight wins to start the season.
“I think they are a superb team,” Voss said.
“I know they have had their ups and downs too but their capability is quite high, we know that.
“We were able to get them here at the Gabba I know but we’ve got to make sure that we bring all those competitive instincts that we talk about week after week.”
Matt Maguire was due to have scans on an injured foot on Monday but he could have a readymade replacement at full-back with Daniel Merrett a likely inclusion after six weeks on the sidelines with a hamstring injury.
Ash McGrath will miss four to six weeks with a high-grade hamstring tear.
Another stint in the reserves has proved just the tonic for Travis Johnstone, who starred with 37 disposals against North Melbourne.
Voss said Johnstone was a player who responded well to being put under pressure by the coaching staff.
“He likes the foot on the throat mentality,” Voss said.
“That’s what he feels works best for him. He likes to have that constant prod and he seems to respond to that.
“He played a fantastic game for us... we rate[ed] him our best player on the field on the weekend by a fair margin.”
