The phenomenon in my house is known as "man maths".
It is this process which leads one to do things like sell a perfectly good S4 Aero and buy an Aeromax, with the kind of justification that is
'well I won't need to get a new car to drive to clients then, so actually it's good value'...
(Yes I really said that...)
This is also the process that means my wife is currently hearing that a Nissan R-35 GTR is a 'sensible' family car, or that a porsche 993 C4s is a smart investment, or that a Fiat 500 Essesse is a sensible runaround.
Luckily Liz is smarter and better with money than me, so will (usually) prevent me spending money I don't have on cars I don't need.