The whole fiasco behind Unity and Mir, and Canonical's propensity to reinvent the wheel at home.
Snap. Anything [wait... wait... wait...] Snap.
That said this is usually fixed by upgrading it into Mint, and Mint is pretty much a "normie" distro, so you don't need to go out of your way to install Gentoo or say "I use Arch BTW".
EDIT: in other words there's enough shit to throw at Ubuntu, we (people in general) don't need to make it up like OP is doing.