It's not just about running difficult arcs, per se. It's about running content that isn't a mindless "run through and slay things". It's about getting your spandex-encased heinie handed to you and just brushing yourself off, laughing, and commenting "Well, that didn't work..." And then once you've switched chars, thrown yourself at the wall a few more times, and finally succeeded.. that's when you switch things up and go play an easy arc and make snarky comments to your new-found friends the entire time.
If you like discussing arcs, builds that annihilate bosses without blinking, running the difficult arcs, building the arcs and seeking honest feedback about them, then I highly recommend joining the Aleph global channel. You're not required to do anything if you do, it's just another place to find friends and talk about the harder sides of CoX.
I was not paid to make this endorsement. Your mileage may vary. Offer excludes Emp sets. "Your mom."
