I kind of equate grappling newcomers to playing poker with vacationers in a casino. There's rarely logic to what they're going to do... which makes it more interesting. As the biggest guy in our class (second only to the instructor.. I'm 6'2 230lbs) I can tell when my size has an advantage. Particularly with my longer legs, I can use the rubber guard fairly easily... and I can power out of lazy submission attempts. However, there is another guy in the class that's submitted me and is obviously less experienced (he is stronger than me though)... and it pissed me off to no end (specifically because he was trash talking ahead of time). Sometimes you just gotta learn to blow it off. The next class I tapped him in 30 seconds. shit happens.
Thanks to NikosCC for the sick sig!