I was a building society manager in the 80s, & I used to see the same mentality with some of the morons we lent money to.
A guy applied for a mortgage & told me his house was worth £95,000, a huge amount at the time. It'd buy you a decent 4-bed detached with en-suite & double garage (this was in Bristol). When our surveyor went round, he discovered it was a 3-bed mid-terrace in a sprawling urban area, with a tiny garden & no off-street parking. Top "ceiling" price for the locality was about £50,000.
When the surveyor went inside, the owner showed him all the home "improvements" he'd done - Neff kitchen, three toilets, two showers, gold-plated taps & light-fittings, marble effect worktops, hessian wall-coverings, etc. etc. He's totally overcooked the place. His reasoning was that because he'd paid £50,000 for the house, and spent £45,000 on tarting it up to look like Elton John's boudoir (& I apologise to Elton now), ergo it was worth £95,000.
It never occurred to him that there was a maximum amount that anyone was willing to pay to live in that street, and that none of his additions had added a penny to the value. Arguably, they'd reduced the value because the house was personalised so much to his (******' awful) taste.
