My wife and I race (sometimes, most times I 'participate') triathlon- so definitely my share of road riding, but I find it very very boring, especially training rides.
I have a BMC TF01 (FS)- I LOVE trail riding, I'm not very good at it, especially extremely technical stuff, but it is far more enjoyable than riding on the road. A lot of idiots and people like others who have posted in this thread that make road riding alone fairly dangerous.
I'm pretty much the same with running, I will run on the roads/sidewalks/bike paths with my wife, but if I'm going alone - I'm hitting the trails. Trail running is far more enjoyable for me.