The thing that made playing ME3 worthwhile after that ending(s)
After not playing the game for a long time after my initial play-through, I finally put the ending and everything behind me and started a new play-through around last summer. I didn't care anything at all about the multiplayer aspect, but on a whim tried it one night ... I have been addicted ever since.
As others have alluded to, I'll remember ME3 for showing me what a great time multiplayer/co-op can be and that I don't have to rely on stories / solo campaigns for my escapism. Also, I haven't been around this forum for too long - but the community for the most part seems a great place. Plus I really dig all the innuendo. 