I spent the vast majority of D1 as a solo player. Most of my raids and nightfalls were done via lfg. I avoided trials like the plague since I'm bad at pvp, but I always did iron banner because it dropped gear to increase your light. Even as a solo player, it always seemed like there was something fun to do. Getting matched with a couple good randoms and running strikes for hours, and maybe adding another person to your friends list. Going into crucible knowing that even though you may not be good, eventually, everything will click, and you'll play better than you believed you could. Going to skywatch and finding 3 or 4 other randoms waiting for the warsat or enemies moving against each other, just so you could melt Urzok. I still play D1 regularly, and am now part of a D1 clan. For me, D2 lost the rhythm. Between the static rolled loot, the dumbing down of the subclasses, moving special weapons into the heavy slot, and numerous other changes that I don't feel were necessary. I tried Leviathan with a clan, but I didn't even find that fun. It seemed contrived and gimmicky. I've played through both expansions hoping to recapture the feeling that kept my playing D1 on a daily basis, but it just isn't there. Eventually I realized that doing the milestones was just going through the motions. The enjoyment was gone. If you're enjoying it, that's fantastic, and I wish you the best!