That guy is tough to explain. The main characteristic is that he is a guy who is, actually, in pretty good shape, regardless of the sanity behind his workout routine.
Our own that guy (lets call him DB) is actually a really good guy. DB is a smart guy, who has time to read up on fitness stuff. He knows enough to wade past the Muscle Mag and Flex magazines, and finds decent blogs to read and gets his info from pretty good sources. DB has no background in Exercise Phys, which makes it tough for him to sift through the endless amount of crap available to read on the internet.
One of the things that makes DB that guy is his status as a beginner to exercise; as long as he sticks to something for 2-3 months he will get some sort of results. This makes the TRX workouts fantastic, and the navy seal circuit training a killer, and the Oompa Loompa designed KB program he is doing now is the greatest thing ever!
Another interesting trait to our DB is what he thinks counts as "ok" at the gym. Theres the time he broke his finger on a plate shadow boxing in the weight room. There is his endless chatter, which mimics a house full of chickens. Above all, though, is the smell. Our DB thinks that rocking the same pair of gym clothes all week is "ok" because he is at the gym, its ok to smell. I agree, being sweaty at the gym is a great thing; and yes, for some people that makes a little funk goes along with it. However, smelling like the inside of a horses asshole does NOT need to occur at the gym. If I can tell you are in the facility by catching a whiff of your stink-trail, that is not a good thing.
This individual had been at the gym for about 2 years before he came to me to use one of his free sessions. I had observed him do his bodyweight circuits, and TRX circuits and his Charles Staley High Density routines, and I decided to teach him the good shit: we went right for squats and deadlifts. You know what? Homeboy didn't know either one. His squat lacked proper depth due to some flexibility/mobility issues. He had never deadlifted and had trouble with lower back rounding. He kept telling me, "oh, I can feel that my left glute medius isn't firing, thats making this really tough, my hip keeps hiking, my quadratus lumborum isn't activated, wah wah wah".
Excuses are like assholes, they all stink and everybody has one.
Now, let me say, that some people have legitimate injuries or malfunctions that will not allow them to perform certain movements. He is not one of those people. He reads too much and thinks he knows too much to let him do a strength movement correctly without injuring himself. DB is a great example of a guy that started at 0 as beginner, jumped right over the basic stuff and landed at level 5 with all the High Density workouts and speciality circuits.
I can't stress enough the importance of starting with the basics. Having a baseline level of strength will make everything you do after that much more effective. Plus, the basic lifts are the best for any level of lifter. Seriously.
Now, go lift something heavy. But make sure you bring new gym clothes with you.