There's so many examples I can give that illustrate my Statement, but to name one instance, I'm the Harbinger of The Companions and I'm exploring a part of Skyrim I haven't before, Rift, and I brought Vilkas with me. While on my travels, Torvar and Athis come out of no where and Torvar stops to say " It's my favorite drinking buddy! " and then the two of them continue on their travels. It was really tempting to follow them, but I had more important things to worry about.
You might be asking, what is so dang significant about this scenario? Well I'll tell you, this goes to show that other members of The Companions do quests to, they have their own lives and do their own thing, it's really exciting to see them doing something other than sitting in chilling in Whiterun.
What cool things like this have you seen in the game thus far?