He seems to think that since what he's interested in is getting into the dungeon and killing monsters, that it somehow makes him a bad player. He's uninterested in the talking and side-quests, and focused on when his next combat will come from. He is quite enthusiastic about getting everyone back to the dungeon and he often apologizes for this behavior.
I've told him over and over that it's ok. Of course on the other hand, I also give him a hard time. I just think that his opinion of himself as 'a bad roleplayer' is silly. He's been playing in a game of mine weekly for over 2 years. One was a Shadowrun game that ran half a year.
There's a guy, who did a bit of reinventing of the hobby of RPGs. Something that had disappeared since roman times, he brought it back into vogue. You might of heard of him - Gary Gygax. In his home campaigns he had a set of house rules. Here is the list. I'd like to point out one particular item.
Gary IDs most magic items immediately (charging large sums of money when they return to town to rest & recuperate for this service). (This is because the players are anxious to get back into the dungeon & don't want to bother with in-town adventures.) Potions must still be tasted to ID, though. Usual items require a trip to the striped mage.
So you see, that player is actually hewing closer to the original implementation of the Dungeons and Dragons player, then the more modern ones. He's doing a more authentic version of roleplaying then the entire rest of the table.
Now I just need to get him to stop playing computer games at the table. Snuck that sucker right in under the premise of 'keeping up with his fantasy football scores'. ;-p