It was kind of an emotional purchase but it's been working out so far!)

You really have to take emotion out of the hunt.

I would file an incident report of being threatened with the police.This way you have something on record in case another event happens you can show a pattern.I believe the tenant is trying to intimidate you to get some of the deposit back.Keep your emotions in check and communicate everything in writing.Once the former tenant see you cannot be intimidated or manipulated they most just move on.

It's still nice to get but the emotional payoff is not as high as the first million, first 10 million, etc.If you treat people right, learn the skills and knowledge, find your passion, and never give up that is most of the battle to success.Very few people possess all these traits together.

Even when they are needy, demanding and manipulative, I find the mental and emotional space to deal with them.

Given a reasonable asset allocation, emotionally stable personality and a decent time horizon, combination of index funds/RE will beat either index funds or RE alone, 9 times out of 10. 

The criteria you come up with will keep your emotions in control.

Plus there's the emotional stress of financial risk and I'm guessing you have enough on your plate :) Basically my advice is, don't screw up your life because you're in a hurry to acquire wealth.

Since they are not owner occupied it is not an emotional decision... you can either significantly improve the NOI or not.

One more tip – people remember stories that trigger their emotions.