I would love to play with people who are "good" at D&D. A few years ago I was in a D&D 3.5 group with a guy named Brad Willer. He was very fun. He came to have a good time. He made jokes and laughed at other people's jokes. He smiled. When combat started, he would get into the action and dish out damage. He didn't know the rules so well that he could rules-lawyer it, but he knew the rules well enough to make an effective character. So, he contributed to the team.
He bathed. He was fit. He was normal and well-adjusted. He showed up on time. He had a good story to tell if there was down-time. He was relaxed and never got pissy if people did unexpected things (like talking about a TV show for 20 minutes). He tried not to metagame. He tried not to steal the spotlight or otherwise micro-manage other people's characters.
He never undermined/berated/argued with the DM, but if he felt the urge to second-guess the DM, he did it pretty damn nicely. He'd accept house rules, even temporary on-the-spot made up ones that conflicted with the books. When it was his turn, he knew what he was going to do -- nobody ever set a timer on him, which is way more than I can say for myself. I get timer'd a lot, as I hem & haw and try to figure out which of 30 spells I want to cast. But not him.
Lastly, he gave his characters personality. We never LARP'd, and even thought just speaking in character voices was weird. But even with those limitations, he managed to have a hilariously over-the-top warrior who was certifiably dangerous, arrogant, and endearing all at the same time. The other players rooted for him.
So, yeah. I think you can be good at D&D. I wish more people were. Hell, I wish I was as good as Brad.