Hey all, I wanted to see if anyone can help me determine whether this is normal for a 4-unit in a B/B- neighborhood. Things have been MUCH better in 2018 than in 2017. The rent has been getting collected with no major issues. Here are the problems so far that I've faced this year.

1) February 2018, a tenant wanted to move out early (after 6 months) due to "personal reasons". She moved out with no major issues, and we kept her deposit. 

2) October 2018, one other tenant got a dog saying it was a therapy dog. We normally don't allow pets, but he provided sufficient documentation that it was a service animal, so he was allowed to keep it. This went on for a few months, but around September, the downstairs neighbor was complaining that the dog was being too loud. He was notified, but he took no major action. He had one month left in his lease and was not allowed to renew. He didn't pay the last month of rent, and we evicted him. 
3) November 2018, another tenant is now complaining that his downstairs neighbor is harassing them for being too loud. He states that she is getting confrontational and hitting her ceiling with a pole when she hears noise from their apartment. She is also threatening to lock their access to the basement if they don't stop - not sure how she can do this. She has called the police on him. The police came by, and didn't find anything of major concern, apologized to the tenant and left. This tenant appears to be pretty shaken up by her actions. This issues is ongoing, and my manager should be dealing with it soon.

This property is professionally managed, and I frequently communicate with my property manager. My question to all the experienced investors is, is this normal? If I should expect this sort of thing, I should probably learn to accept that this is how it's going to be. However, the uncertainty in what lies ahead in this type of situation is what really stresses me out. Any input would be greatly appreciated.

Thanks,

Satya