I second a few of the things said here. Not getting emotionally attached is hard, especially if you are house hacking and moving out of properties that you've put a lot of time and energy into to turn them into rentals. I have to constantly remind myself that it's a business, and there will be expenses and some damage, and not to get so tied up in the property remaining the perfect condition I want to believe I left it in. Really diligent tenant screening has helped me with this big time, I worry less now, but in the early days, it was tough for me.
Mulitple turnovers on the same day is tough too. I live and manage in a college town, so all properties basically Turn on August 1st. When 3 or 4 properties turn in the same year it's overwhelming, especially with a full-time job still. I've found that again finding better tenants has helped this as there is less to do, but also really trying hard to retain tenants has helped my sanity a ton. I incentivize tenants to stay if they are good tenants, with either no rent increases for another year, or a smaller increase, or sometimes, I'll even give a one month discount for resigning if they are really good. Any property I can keep rented to good tenants is one less I have to turn. It's also helped a ton to again run my rentals like a business, and expect expenses, like hiring cleaners, painters, and so forth. I used to pinch every penny and try to do all this myself, I'd get my mom and sisters to come to town, I'd buy pizza and beer and we'd go from house to house cleaning, painting and fixing things. It was a nightmare, and it's late July in Colorado, so it was always 100 degrees out. Recently I've realized that a few hundred bucks to hire help allows me to focus solely on the bigger issues, and not worry so much about things like touching up paint or cleaning bathrooms.
Honestly though, over the past 10 years, I've learned to really enjoy being a landlord. I create great relationships with most of my tenants and having to deal with them and random issues is usually not too terrible anymore. Great post @Krystallin Baker , and thanks for all the insight in these answers!