It's a measure of how much a car holds your attention if, when heading into an airport on the way to - say - a media launch for something new and exciting, you give a wistful glance over your shoulder at the car you arrived in.
I've left the M in the car park on the way to try out the new Mercedes C63 AMG coupe in Seville (yes, yes, we know - it's a hard life etc, etc). It's a trip that ought to get even the most jaded of hacks slavering in anticipation, but the 1-series M I've has definitely earned itself one - if not two - backward glances.
We're only a few days into our time with the Valencia Orange M car (or a couple of months in compressed '.zip' time), and we've already covered 1200 miles on some fabulous roads (a trip you'll be able to read about soon). But I still have an urge simply to get in it and drive - with no particular destination in mind - and if that isn't proof enough that it's worthy of the famous M stripes I don't know what is.
I reckon the combination of a short, wide wheelbase, an endlessly eager turbocharged in-line six and the absence of too much electronic messing is definitely enough to keep even the most demanding driver more or less endlessly amused - and reluctant to get out even after 10 hours behind the wheel.
There's one thing that might stop you from giving that last longing gaze before you leave it overnight in a car park, though. The 1-series has never been feted as a beauty, but those bulging arches, particularly at the rear, do seem to make BMW's smallest saloon a bit awkward visually... Perhaps this is one of those cars that look better from the driving seat...