While like others I have a destination in mind I try to make the ride as spontaneous as possible and try to focus on the moment not time,distance,direction etc. or any planning of the ride in great detail.When I take off on a day or even weekend ride it is because I feel like it and usually an impulsive last minite decision .Having said that I try not to get totally lost as that can be dangerous around here.I do vary the routes usually going in a circular loop and always starting and ending at my front door.Also I combine other activities with the cycling at my destination/destinations such as hiking,lounging at the beach/outdoor cafe/picnic table or walking around the mall/store(a favorite to escape midday heat lol) etc. so as Michael mentioned the bicycle is sort of the mode of transportation or tool for adventure as it puts you in the right frame of mind.Also loading the bike even if its just extra water/food/clothes more than I will use tends to put me in the right frame of mind both due to the extra challenge and the association with past adventures.I just used a duffel bag on my back for this before I got a rear rack as this seemed to ride lower on my back than a backpack thus less stressful.