who taught you the hidden secret of owning rental properties instead of just selling RE as a realtor?

Plumbing by-passes or abandoned lines; collapsing sewer lines; badly corroded supply and waste lines (both can be from inside or outside corrosion) fixtures with very hard to find components; hidden electrical junction boxes...or non-existent boxes at junctions; outdated and/or underrated distribution panels; knob and tube wiring improperly connected to, or extended with, romex; Switches wired incorrectly, breaking the neutral instead of the hot side; no, or poor grounds for improper outlets; overheated connections, outlets, switches, and light fixtures; improper wire sizes for circuits and overloaded circuits; and plenty of others...all very costly to troubleshoot, locate, and correct individually.

Most people that have never been self-employed have little idea of all the hidden costs involved.

You won't give up yet....after a while you finally find a gem,  but it ends up being a total rehab or gut project and if you are not equipped to deal with that or have the knowledge or time to do it....you are now bummed and decide that you can't in fact be a real estate investor and now you are going to have to suck it up and work that 9-5 job you hate forever and hope your retirement account is healthy when you retire.

There's a ton of hidden expenses that you don't realize till you have some experience under your belt. 

The exception is the rare occurrence where there is hidden seller desperation and you can negotiate a big discounted purchase.

◦Make sure the company does not entice you with a low management fee then nickel and dime you with miscellaneous and hidden fees.16. 

Rate, points, fees (other hidden fees).

(Ending at around 110k cause of many hidden unknowns).

It goes a long way to ensuring peace of mind or highlighting red flags that get hidden when people just talk a good game.