While getting out of my friend’s car (I’m the rider and he was the driver), when parked, car door got a few scratches at the bottom due to bushes on the sidewalk. Should I pay for the damage?
While this is CarTalk and not CarLegalTalk, I’d say yes. A good friend would offer to touch up the scratches or have it done. Whether or not the car’s owner takes you up on that is his decision to make.
Yes you should!
The next time your friend washes the car, say you’ll remove the scratches with this.
http://www.nufinish.com/products/scratch-remover
Tester
Assuming you were the one operating the door when the damage occurred. You should definitely at least offer to fix the damage and/or pay for the repair. I don’t see how this is even a question really.
That’s a tough one. If I was the driver I’d just pretend it didn’t happen, or say “fuggit’bout’it” then buff it out myself when I had a chance. Or more likely I’d just wait until next I waxed the car. If the driver-friend seemed upset, I’d say you should offer to try to rub the scratches out yourself the best you can using an inexpensive product, but you wouldn’t be responsible beyond that; i.e. if the friend insisted the entire door be repainted, or only a pro-buffing job would do, that would be asking too much imo.
This reminds me of another story. Oh no, here he goes again! … lol … One time I was invited to go on a fishing trip hosted by the BF of a co-worker. This BF of hers, I’d never met him before that, he turned out to be an airplane mechanic, and was a little on the retentive side. I guess that’s a good thing for an airplane mechanic, but on a fishing trip? Not so much 
Anyway we all meet at the campsite about 6 pm, near a lake, we have a little group cook-out, sit by the fire, play our guitars, had some beers, and as far as I could tell everything amongst the group was perfectly fine. The BF didn’t seem to like my choice of music, but I just ignored that. The next morning we wake up pretty early b/c apparently this wake-up-early-thing is what fishermen do. Which means most of us are a little cranky. But we still bear the burden of the early morning walk and make our way to the boat, which the BF parked there the day before. The boat is one of those aluminum fishing boats, very basic, no top, 3 rows of wooden planks to sit, with a 5 hp portable outboard motor just powerful enough to position the boat for where you wanted to fish, not much more.
One thing about boat fishing I had prior discovered – fishing doesn’t really interest me, but I’ve done it a few times — but it’s really hot sitting in a boat on the lake. So I brought along a couple of coca colas and a little ice. When we got to the fishing spot, we just parked the boat and let it drift, I put my line in, and opened a can of coke. Pop! Well, the BF looks at me like I’m Bernie Madoff and I’ve made off with all his investment loot. He says to me, without looking at me, “No drinking of any kind of liquid except for water allowed on my boat!” Since I’d already opened the can, I figured I’d drink it anyway, and just not drink the second can in his deference. He didn’t say anything, but seemed pretty perturbed that I’d defy orders and drink the soda anyway, him being captain of the boat I guess.
Anyway, back at camp he appears to be upset, but not quite ready to pick a fight with me. We had caught 4 lake trout, so I ask him if he’d like me to prepare the fish for cooking, try to smooth the soda incident over. He says “sure”, and hands me the fish. So I gut and clean them very thoroughly, then I cut off the heads and tails. I don’t like seeing the fishing looking at me from the plate … lol … When I bring these prepared for cooking fish to him, he goes ballistic! "Why did you cut off the fish heads? Nobody cuts the head off a fish I catch!!! And caught in my own boat!!! " … lol …
Anyway, as you might expect, this dinner didn’t turn out to be quite as enjoyable as I had imagined. What with fish w/no heads on them readily apparent on the plate. OMG!! … lol … Then as if to put a period at the end of a sentence, I throw a piece of paper from a candy bar wrapping into his garbage can he had there by the camp stove; he picks it out and hands it back to me!!! I throw it in the fire, he picks it out of the fire and tells me to take it to the campground garbage can about 100 yards away … I give up and say goodbye to everybody and as I’m walking toward my car I hear him sayin “that George guy is never going in my fishing boat again”* … lol …
(*) This part turned out to be true.