I usually run alone. Sometimes I'll join up with a local running group who meets on Saturday early mornings, and I've made some great friendships with a bunch of women who love to run and are all about the same pace for long runs. Sometimes in NYC my brother will deign to jog along with me for a couple of miles at a (for him) laughably slow pace. But by far most of my runs are solo by choice. I love that time for thinking, listening to music or podcasts, taking it mile by mile in my own company.
But every once in a while I get a treat: to run with my husband! He's coming back from foot surgery last year and this was our first run together since then: 3 miles on a super-crazy windy day (gusts up to 20 mph on the lakefront). Annoyingly, he's faster than me. Though I loved it anyway.