You should probably not judge a book by its cover, but in the case of cars, you will seldom be wrong if you assume something shaped like a Porsche 911 will be fast, something like a Honda Odyssey will be roomy and something like a Toyota Camry will be a safe but staid bet.
It has gotten a little murky with the endless proliferation of sub-segments and variants, no doubt. And as with most things, there are also exceptions to the rule. The new Jaguar XF is one such exception.
On the surface, the car appears similar to the previous XF - dignified, subdued, gentlemanly and, yes, "well-behaved".
But it is actually quite a different beast. The latest feline is decidedly sportier and may well be targeted more at the BMW 5-series than the Mercedes-Benz E-class.
In fact, when you drive it with verve, twisting the rotary gear selector to Sport, the XF can be downright rascally.
JAGUAR XF 2.0 PRESTIGE
Price: $229,999 with COE
Engine: 1,999cc 16-valve inline-4 turbocharged
Transmission: Eight-speed automatic with paddle shift
Power: 240bhp at 5,500rpm
Torque: 340Nm at 1,750-4,000rpm
0-100kmh: Seven seconds
Top speed: 248kmh
Fuel consumption: 7.5 litres/100km
Agent: Wearnes Automotive
Squeeze the throttle and the cat pounces like its muscles were primed for that very moment. In just seven seconds from standstill, the speedometer is pointing at 100kmh.
In the process, it grunts and snarls like a UFC fighter - quite uncharacteristic of its pinstripe-suited persona. It is, of course, not as aggressive as the over-the-top Jag F-Type, but definitely edgier than rival sedans from Germany.
So what you get is an executive sedan you can commute from boardroom to ballroom in regal fashion, but one which keeps you entertained along the way.
A hint of the XF's misleading nature can be found at the rear of the car, where you will see a "2.5t" badging. The car is actually powered by a 2-litre turbocharged engine that makes 240bhp and 340Nm.
The badging is to distinguish it from the 2-litre 200bhp unit powering its smaller sibling, the XE.
While Jaguar has long distinguished itself from its German rivals, it seems to have embraced their preference for confusing nomenclature. But to be fair, the car does feel more like a 2.5-litre. It is too frisky to be a 2-litre.
Its engine does not take all the credit for that though. An aluminium-intensive architecture has kept its weight below 1.6 tonnes, which is pretty impressive for a car that is slightly longer than the Mercedes E-class and BMW 5-series.
Elsewhere, the XF has an equal footing as well. Build quality is commendable, cabin ambience matches most of its rivals' and its level of refinement is within expectations.
There are moments when it betrays turbo lag and others when it feels a little jerky when crawling along in second gear. But these are rare. Most of the time, the car is a breeze to drive - thoroughly responsive and thoroughly enjoyable.
As for ride comfort, Jaguar seems to have moved away from being pillowy and pampering. Instead, it offers controlled pliancy.
On paper, its wheelbase suggests superior space. But in reality, it is no better or worse than what the Merc or BMW offers.
The car is also decently equipped, but its navigation is not among the most friendly systems around. And it does not have an auto hold.
But if you are shopping for a premium performance sedan, ignore these things. Know instead that you can, for once, look beyond the usual suspects.