I often fly alone simply because there is very little activity at our club flying field.
Most of the time it is nice to have other people around. Sometimes I prefer to be alone, especially during calm evenings with almost clear skies and a setting sun at the horizon. On those occasions I like to fly low and slow making feather light touch and goes and circuits. I find this very relaxing, almost like meditating.

On a safety point, if you fly alone bring a cell phone in case of emergencies! I had an accident at the flying field about two decades ago that left me almost incapable of driving the car from the flying field. I had a serious propeller cut in my arm caused by my own negligence. There was a lot of blood and after a while I managed to apply a tourniquet. I was severly chocked and fainted while walking to the car, but eventually made it to the hospital. After that accident I bought a cell phone.