I'd become tired of having to always pay attention to the direction & speed of the wind... how the clouds are changing... weather forecasts, temperature, etc. because you're so exposed when you're on a motorcycle.
When you're in a car, you just go without much thought because no matter the conditions you're pretty much protected.
I even considered being done with motorcycle travel mostly because of the raw elemental exposure, and the all too intimate struggle with insects & wild animals who want to steal your food.
Now I think that all of these inconveniences actually help to force me awake and paying even closer attention to detail. It's no fun trying to outrun a storm, boiling in the sun, shivering in the night, or chasing the raccoons away from your food. But if that's the price to be forced into complete awareness of every moment of living, I'll gladly pony up. :)