Like an applicant asking if we would put in hardwood floors, or paint the walls a different color, or buy them room-darkening curtains because the street lights might keep them awake at night, etc. 

., and is bickering the entire time during a showing-- showing up with rude, uncontrollable kids- showing up in a filthy vehicle- calling to tell me they will be late for an appointment because they're stuck in traffic - and I check Google traffic to find out there is no traffic jam - so, they're lying to me- using a relative as a reference- blowing off an appointment (automatic denial - they'd often then call for another appointment - uh, nope)- tenants going through a divorce (they won't end up honoring the lease and there is almost always drama with the ex)- being really picky during a showing - asking if we can change the closet to add another rod, or to change the paint color or can they have hardwood flooring instead of carpet, or will we pay for room darkening curtains if the street lights are too bright - these tenants will be constant whiners.These are all I can think of right now, but are all things I learned about the types of personalities that will cause problems. 

Mess & style of tenant will 'color' the perception of the prospect.Move'm out, clean up/paint as necessary. 

I provide paint colors for them and tell them the cost of flooring in case they damage it.6. 

However, the very same day we signed the lease and I handed them the keys, they asked if I could re-paint some of the walls to a different color and change out the closet doors to mirrored doors.  

can I paint it a weird color?  

We've all had or witnessed tenant horror stories but I'd caution against letting that experience, mismanaged as it was, color your actions now in a way that is stressful or worse might inadvertently open you up to a breach of contract or breach of quiet enjoyment suit. 

I couldn't stand having others involved in my investments, who could tell me what color I could paint it, or tell me I had to pay for garage doors, on and on.It would be good if you could sell it, as Greg S mentioned.  

I see where that also probably colors your perspective.

Painting I'd say something to the effect of 'sure you can paint the interior whatever color you like but it needs to be restored to the original color and quality before you move out'.