Python strings are immutable, but only sometimes
My favorite Python WTF "feature" is that integers can have have the same reference, but only sometimes:  >>> a = 256
  >>> b = 256
  >>> a is b
  True
  >>> a = 257
  >>> b = 257
  >>> a is b
  False
  >>> a = 257; b = 257
  >>> a is b
  True

Sometimes I think of Python as the Nash Equilibrium[a] of programming languages:It's never the absolute best language for anything, but it's hard to improve it on any front (e.g., execution speed) without hindering it on other fronts (e.g., ad-hoc interactivity), and it's never the absolute worst language for anything. Often enough, it's good enough.Python might well be "the least-worst language for everything."--[a] https://en.wikipedia.org/wiki/Nash_equilibrium