Collecting magazines. I love finding a new magazine. The minor perk they give are neat, but I get more jazzed by the cover art. The fact that no two magazines are the same is wonderful. The Wasteland Survival Guides never cease to give me a chuckle with their crude, almost zine-like cover art. And there's so many of them. Who needs Bobbleheads?
The game world is fun to explore: beaches strewn with driftwood and debris, gloomy swamps, shanty towns, hidden bunkers, the larger places like Diamond City and Good Neighbor, raft forts, sinkholes, highway bases, raider strongholds like Libertalia, all the nooks and crannies that hold silly things like teddy bears propped up like people, and more. However, I am rather let down that exploring under water is so boring. So much sea and nothing to do down there.