You know what I love the most about roadsters? That they're so unapologetically useless at doing anything other than performing the one simple task they've been designed for. And that is putting a smile on a driver's face.

It's a single-minded focus on fun that's impossible not to love, and it means that (just like pizza) even the not-so-good ones are still pretty good.

Happily, though, the all-new BMW Z4 isn't one of the not-so-good ones. In fact, in the M40i guise we've tested here, it's brilliant.