Bungie, please, make at least some kind of matchmaking for raids and nightfalls in D2! Not everybody has a ton of friends playing this game, and lot of people are not really that much social to run around and ask everyone to take them into a fireteam for a raid. Therefore these people can't complete raid quests you put in the game! You can learn from World of Warcraft example, where they have different difficulties for raids, and for some of them you can use a groupfinder tool!