quite the best, the worst, etc. something

quite the (most something)

Having the most of a certain quality. ("Quite the" is followed by a superlative adjective and the noun it describes.) Her speech was quite the funniest thing I've heard all year. It wasn't quite the worst book I've ever read, but it wasn't far off.
See also: quite

quite the ˈbest, the ˈworst, etc. something

(informal) absolutely the best, worst, etc: It was quite the worst film I’ve ever seen.
See also: quite, something