I don't, but I have seen people who do. They did not seem at all bothered by the lack of gears. I imagine they walked up the steep hills, but so what? I have walked up more than a few inclines, and I have 27 gears.
Both were riding old bicycles that did not fit their bodies, with under-inflated tires. Gear shifting on one of the bikes was iffy. Nevertheless, riding three-speed bikes seemed to be less relevant than the fact that they were seeing and riding through beautiful countryside.