Very little to say about this, except that it is in heavy contention for the happiest, sunshiniest, poppiest, most joyous song I've ever heard. Take Karen Carpenter's original, performed with measured contentedness and a sprightly but low-key beat. Now let an all-female power pop/punk group from Japan grab hold and blast through it.
Shonen Knife doesn't care that their rhythms might be a bit off, or that they can't quite sing "world" right, what with its tricky "rl" combination. That's what make it so fun. They power through "Top of the World" with such unabashed playfulness, it's impossible not to enjoy it. Or dance like a Muppet or a Peanuts character with it. For me, songs like this, even more than Nirvana, guaranteed that the 1990s would not suck.
From "If I Were A Carpenter":
A slightly edgier live version complete with lyrics: