Fun fact: 9/10 users with no linked gamertag are better than you at Halo. That doesn't necessarily mean that I am; but it does mean there's a pretty solid chance.
You don't go out and play soccer with the intention of losing. You don't play poker with the intention of losing. You don't go to a betting shop and put money on the team you think will lose. You don't ask a girl out with the intention of getting turned down. You don't go abseiling with the intention of falling to your death.
Apply the same logic to videogames. Failing isn't fun.
Similarly, it's perfectly possible to walk into an art gallery and think 'that looks pretty'. It's perfectly possible to drink a glass of wine and think 'that was nice'. It's possible to see an old building and think 'that's cool, I wonder how it was built'. That doesn't mean you're able to appreciate, understand or enjoy any of those things anywhere near as much- or even in the same ways- as an art critic, vinter or architect would.
Again, apply this logic to a videogame. If you're 'bad', you're less capable of understanding, appreciating and enjoying the game. That's not an unreasonable comparison. It applies to virtually any product, service or experience. If you don't 'get' what you're looking at, you can't enjoy it in the same way as someone who does 'get' it.
[Edited on 03.01.2012 1:10 PM PST]