I usually ride on my own on little things like Leedstrials. But I get bored pretty easily on my own, I usually only ride for an hour or so max, whereas on a group ride I can ride for hours and hours. It definitely helps if there's something nearby to ride on though, even just a few secluded curbs are enough to have fun for a few minutes, especially if you're itching to ride :P
Don't use TF to judge British people. We are not all illiterate clowns. And yes, we have cars, but over here we call them "horseless carriages".