On helping other people accept who you are

That's a pretty lofty title for a post about politely telling people to fuck off.

My parents were at a festival yesterday and ran into the friends we're camping with soon. Apparently, the friends were all, "Oh my gosh, Rachael is going to have so much fun hiking and stuff!" and my mom was all, "Yeah? Good luck with that."

My mom knows I'm an indoor kid. The things I do in my leisure time - reading, knitting, baking, dying my hair - those things are best done indoors. That's where I'm happiest. But every time I agree to go on a trip like this, well-meaning friends decide that if I just knew better, I'd love hiking, or camping in general, or Frisbee, or fishing, or whatever stupid thing they want to do. It's not like I'm a huge Debbie Downer, complaining the whole time, but I also don't pretend that HIKING IS SO FUCKING COOL YOU GUYS when seriously, looking at rocks is pretty boring, and I could be back at the campsite getting drunk.

This happens a lot with sports, too. I'm one of the least competitive people alive (at this point, some asshole always says, "I bet I'm less competitive than you are!" and I always agree that it's probably true.), which means I don't really enjoy most sports, including bar-type sports like pool or darts. Friends always assume this means I'm not GOOD at these things, and if they just show me how to do it well, I'll suddenly appreciate it and want to spend my free time doing it. This theory is dead wrong. I'm actually pretty good at darts, in fact, but I just don't like playing. That's all.

So. I was going to ask this question then try to answer it, but then I realized that that anecdote about camping happened yesterday, so apparently I don't have any answers about this. I turn to you, O Internet:

How do I politely reassure my friends that I'm having a fine time, and also that nothing they do or say is going to convince me that the last 26 years have been a farce and I secretly love the things I know I hate?