@David Faulkner  I agree that being courteous and efficient is the way to go with tenants and in business in general.

@Jerry Benson,  one thing I'd suggest, because we had a similar situation, where it seemed like the tenants constantly complained.. is to remind them that "renting is  a 2-way street, and you want them to be happy, so if they aren't happy in the house or they think too much is wrong with it, you'll let them out of the lease early"... along those lines, it's professional, courteous... but also indirectly tells them to stop complaining or leave.  

For those who I know aren't going to be approved, I usually send a courteous email with a brief explanation.  

Their staff is courteous, responsive, and efficient.

Respond in a timely and professional manner to ensure that guests have a positive experience.Manage reviews: Encourage guests to leave reviews and respond to them in a professional and courteous manner.

She seemed very courteous, paid her deposit.

Will you please be more courteous?

If this tenant has been great (maintained the property well, pays rent on time, courteous and respectful, etc), you may give them $50-100 for the headache even though it is completely not your fault.

I am a sucker for a sad story, so they are good a protecting me from me -and they are very fair and courteous to my residents.

Be courteous and leave enough room on the Driver side, so that RV can open their doors.B.