The problem is when speculation is a (large) part of you compensation. You might not do what's right in your work. The same is true for the real-estate market:

The problem is when speculation is a (large) part of you compensation. You might not do what's right in your work. The same is true for the real-estate market: When a corner of the market (eg. apartments in the city) outperforms the rest of the market, you might stop doing what's right for you and start speculating (being in the process of looking for a place to live, I can see several people who lost significant amounts after having bought in 06/07 and sole 10 years later - hopefully for them, they bought the right place to live and did not care about the losses).