I think everyone has their own style and knows what works for them, but I don't think anyone ever got anywhere without at least a little bit of intensity. I'm not talking about the huffing, puffing, throwing weights around intensity, anyone can fake that, I'm talking about the intensity where your mind absolutely tells you to stop, but you just gotta push for that extra rep or nail that 5-10lb PR. There is putting on a show, and there is pushing yourself.
As far training programs are concerned, they all suck if you don't bring it. Someone can hand you to most tested, highest rated, insanely awesome training program ever, but it's never more than 50% of the equation unless you bust your ass in the gym. Work hard enough and eat enough, and even the stupidest programs can work, at least for a little while.