The worst thing about the Many Worlds Interpretation: The name. I mean, wtf? Everett used the perfectly sensible name "Theory of the Universal Wavefunction" which wikipedia at least acknowledges as another name for it. And 'Many Worlds' barely makes sense. It's more "It's not just one world - it's like... completely different to how we used to consider the world and to the extent there is a 'world' at all there are a bunch of them".