In one case, I was a nice guy and allowed the tenants to leave their heavy possessions in the garage (post eviction), without the ability to enter the residence, and arrange to schedule to pick up later.

It usually takes a while, anyway, to close escrow so if they file an eviction right away, then it should be vacant when you take possession as a condition of sale. 

At a minimum you can add to your rental application the questions: "Do you own or possess guns?

I have properties in NC, SC and one in NYC the one i would like to bring up is in SC I bought a fourplex all rented leases in place BUT all four leases were cheep the apartments all looks like Vietnam going through the DMZ bombing raid. so I sent all 4 tenants a 30 day notice that they are to move within 5 days after each lease has ended we rehabbed the entire building as each one left pulled the carpet and got started. we have now finished half the building invested about $30k and re-rented the two finished apt's each went up by $250 a month plus pet dep and extra rent for the pets. and this took all the RIF RAF out and even got a thank you note from the local police and the mayors office for what we did. now in saying all this SC is VERY, VERY Landlord Friendly no rent by the 5th pay $40 bucks for first notice to pay or remove no rent still they have 10 days to pay or leave after that 14 days later the sheriff;s office removes the tenant and retake possession.

However, it would handle spaghetti and fruit peels just fine.Haven't decided if disposals are possessed or just channel the personalities of teenagers.

M question is how to get over this negativity that everyone seems to possess when it comes to being a landlord. 

Probably the first thing you will think of is adverse possession. 

In other words, don't be nit picky, allow them the freedom to live there much in same manner as they could if they owned, after all that is what you leased, owner's rights of possession.

The tenants have until May 31st to move and I regain possession on June 1st.

I had another thought - if I was you, I would email him and tell him that you do not want photos of the interior of your apartment that show your personal possessions made public in any way, because you are concerned about someone burglarizing your home.That way, he can't just post your personal possessions on realtor.com or Craiglist with the address to where someone can find you lovely, expensive MacBook Pro, for instance.And then if you are burglarized, he gets to pay your renter's insurance deductible, since you forewarned him of your concern.