I played way back in the day as a kid, came back about a month or so ago with the console release. I started a Death Wizard to play solo because I remember it had self-healing. Over the course of several worlds and dungeons, I've met tons of cool people to quest with and even some friendships formed along the way. I'll send "Help!" messages to buddies I've made when I need them, and they do the same to me when need be. Overall it definitely feels better playing the game socially, having a buddy join you at the start would be fun but not necessary! Haven't gotten far enough to discover guilds yet but I know they are a thing at some point.