Zdanie

You're anything less than brillinat.

Co to ma znaczyc?

you're absolutely brilliant, more than brilliant, you're a walking think-tanker

you're anything but brilliant

This is where logic comes in, I guess.
If a car is anything but slow, it’s just slow, right? And when something cannot be anything LESS than that 'other something', it should definitely be MORE than that, at least a liitle bit?

u nas znaczy a car is by no means slow

moze masz racje