Simple Technologies

On a daily basis I am simultaneously amazed and annoyed by the technology of the mkokoteni, which is simply a wooden cart used to haul all manner of cargo.  From oranges to sofa's to tires and manure.  It's pulled by a man weighing no more than about 140 lbs and quite often the load he's carrying is five to ten times his body weight.  I never know what's harder - hauling it uphil or downhill.

With the roads as narrow as they are, sharing the road with an mkokoteni can be quite frustrating.  They're hard to overtake with a constant stream of oncoming traffic but at the same time, you don't want to mess with their momentum.  It's not like they have a gas pedal!

Like every city, Arusha has trafiic, but no where near as bad as Nairobi.  Nonetheless, I also wonder how much more crowded the streets in Arusha would be if every load on a mkokoteni were in its own individual truck.  Would traffic flow better since it's a mechanized vehicle or would the congestion just be doubled?

What simple technologies have you encountered?  Did you admire them or did they frustrate you? Are there any simple technologies you use on a daily basis?