Rates drop prices surge. 

Suddenly they'll need extra income to add a hospital, improve the roads, increase police presence, secure our schools, etc.When property values go up, you can expect taxes to go up. 

Then in 2009 the housing bubble burst, real estate prices took a dive, rents came down and your cash flow suddenly disappeared and you owned a once $800K property that is now worth $550K.

For example, at peak construction season in my area, you really have to hunt very hard to find someone willing to paint your project for less than $6/square foot, so when you find someone who'll do it for $2.50, all of the sudden that doesn't seem all that expensive.

Some hospitals are very committed to getting long term staff but there will always be regional surges in demand.

Then it was suddenly frozen one morning and, after an email to the address zillow provided, a voice message to the appropriate phone number, and a form filled out with exactly all the information they request, we get no response for almost a full business day.  

I had a tenant for 3 years that always paid the rent on time, was polite and respectful, then left the place a disaster when he and his family moved suddenly.

Buyers are surprised when a deal that has been going well in the back and forth suddenly dies because someone appeared  and made an agreement.

We then cut the vegetation away and suddenly the backyard was simple and clean.

When we first started looking at multi units (with zero managing experience), all of a sudden we qualified for a couple of $600+k 4-plexes because the income from the units were factored into the banks qualifying equation.