But the harsh reality of it that football is a tough game and the only way to improve is by learning from mistakes.
Kennedy has had indifferent form this season with the gloves for the lowly Jets and Culina has challenged him to bounce back from recent errors that have cost his team vital points.
"We don't want to destroy Ben Kennedy, but we do want to test him to see whether he's going to bounce back," Culina said.
"I wanted to ensure Ben, whilst yes I'm harsh and I thought he can do better, it's not the end of the world and it's how he responds to that which will be a telling factor.
"It's all about growing up and showing you've got what it takes.
"It's no good sulking, because sometimes you need to test players and see what they're made of. If he can't bounce back after this, maybe he does need to have a good look at himself.
"You don't want people who will sulk, because Ben's also been shown confidence by the club for a two-year extension.
"If we didn't think he had the potential, we wouldn't have offered him that."
At 22, Kennedy is old enough to know that a bit of criticism is not such a bad thing as it is likely to help him develop his game even further.
"It gets a bit hard but you've got to try and move on as quick as possible and learn from your mistakes and just concentrate on Friday, which is what I'm doing," Kennedy said. "Obviously they're just trying to help me out. I've got to accept that. This is the way they've obviously chosen to do it, and I'm happy to go down that way.
"If it helps me, I'm all for it. It's part of being a goalkeeper, I suppose. You've got deal with that.
"It gets a bit hard but you've just got to move on from it and concentrate on the next match."