The Carry/Leech system that people have come to expect has it's benefits and it's flaws. I'll admit to leeching, but usually I ask the "carry" what they want me to do, because if there is a chance to help and actually put up a fight, I will. I aim most of my grinding towards making myself a stronger solo player, since tackling the story line dungeons by myself is what I enjoy.
Admittedly, it surprised me that some people will yell at you for touching the mobs. I don't expect to be carried through a dungeon, but more often than not I find myself in the carry/leech scenario, because that's what people have come to expect. Yesterday, though, I was in a really nice party where the "carry" didn't mind whether or not we fought. It was a nice chance to practice actually playing the game. Most of the parties I've been in have been nice people, we've chatted, we've supported each other and generally had a good time grinding.
Although I like to fight, I also don't mind being carried. Some carries do it because they want to help lower level players. It was much appreciated when I was in my low 20's trying to get high enough to solo my story quests (though even then, I was trying to fight as well)
But I do find the carry/leech system has spoiled some players, and it's unfortunate. In one scenario, I was in a party full of people level 25-31. At 31 I was the highest level player after a lvl 35 player had quit. We just got a lvl 22 in the party, and went back in the dungeon on hell mode. I knew we could clear it, if we worked together. What happened was people running around like chickens with their head cut off, then rage quitting because they weren't being carried through. When we WERE clearing the rooms, and could have carried ourselves, if they had listened to the methods I and the lvl 29 working with me were trying to employ to get us through. We'd only had two deaths, mostly because people kept aggroing the lanterns out of the group.
Nobody wants to put up a good fight in a dungeon any more, and its a bit sad. I feel like at higher levels, I'm going to have no choice but to gain EXP by letting other players leech off of me, even though it's not something I really want to do, because no one seems to want to tackle dungeons TOGETHER.