Which technology should we unlearn?

Todd, a loyal MR reader, writes to me:

If you had the power to make civilization unlearn one technology or theory in use today, what would it be?

I’m not ready to say nuclear weapons, which so far have been a major net force for peace, at least until the next one goes off.

Music streaming (or is it the MP3?) doesn’t seem important enough, still I do not think it will improve creativity over the longer run.  In this sector I care more about the total quality of product than about maximizing the sum total of consumer plus producer surplus.

How about the Facebook technology which limits you to 5000 friends?  (just joking…)

Modern ketchup?

Land mines are a possible pick, but that wouldn’t help South Korea any.  Drones are another candidate, too early to tell.

In my rather strongly held view, most technologies are net improvements.

But I think I’ll go with cluster bombs.  Or poison gas.  The Kalashnikov?