The situation: I've just bought a new computer. Sweet. I want to migrate all the "stuff" from my other computer. Cool. They even have a tool for that!
But... Crap. If you've already got an account on the new machine, you can't migrate an account with the same name from the old machine (because, hey, who uses the same name on two machines?).
Ok, re-install, try again...
But... Crap. Can't mount my encrypted backup from the install environment. Ok, create another account with a new name, migrate, trash new account, use old account.
And everything is happy.
Except... Not quite. Apparently not only does it migrate my home directory, but everything! Yea, all those old, broken, Power-PC only libraries? Yup, here to muck up my new machine
Apple migration assistant, you suck