I've never liked solo. One of the main reasons is that I am a bad loser, though not in the sense that I swear and curse at my opponent and call him a noob and lucker or worse. Quite on the contrary, when I lose too much I get demoralised and end up getting the totally wrong mindset, one where I have more or less lost before I even start playing.
I'm quite the pessimist. When I played Magic: the Gathering, I always imagined that my opponent had the perfect counter in his hand, at all times. Of course that was far from the truth, most of the time my opponent would have a just as crappy hand as myself or perhaps a worse one. Though I kept outplaying myself in my head by constantly thinking my opponent had better cards and more luck than me, something that prevented me from taking the calculated risks that could win me games.
While I know perfectly well that both players start with equal opportunities (more or less, at least) and that my opponent can't just automatically counter whatever I do, my pessimism from Magic has carried over to Warcraft. I always expect my opponents to have the best possible counters to my units, to be able to creep faster than me and to be generally better.
I remember one of my first solo games ever. It had taken me ages to gather enough courage to press that play button, and finally I did it. When the load screen came up, I was terrified, and when the game started, I was almost shaking. Of course, I messed everything up. I screwed up the build order, forgot all my plans and ended up losing badly to another Orc player.
My next game was different. It was on Lost Temple, and my opponent was Night Elf. This time I managed to get my build right, and when I went scouting, I located the Night Elf base. My opponent had gone for the Demon Hunter and made Archers from one Ancient of War.
I decided to try some harassment, and I went over and sent my Spirit Wolves after the Archers. One by one they fell down, then the Demon Hunter fell and, frustrated, my opponent uprooted his Tree of Life to try and fend off my Far Seer and my Grunts.
Now I didn't play many solo games after that, and I still don't like solo at all. Though I won that game, and it taught me a valuable lesson: There ARE players out there that are even worse than myself.