Bottle of water!
I stayed (still in the hotel) in Renaissance Houston Hotel on June 2012. I'm staying for 13 days. I called front desk checking if there are any extra charges that are attached to my room before I leave. My company made the reservation and they are paying for the room and the tax. Any extra charges will be expensed to me. 
The guy who answerd me said:
you have "requested" a bottle of water and its been charged to your room. 
I replied:
No I haven't requested any bottle of water, when was that when there is still your bottle here!
He said: 
Yes, you did! He gave me a date which I didn't even bother to listen. He tone was so rude and I tried to convince him that there could be a confustion that I bought 4 water bottles and put them in my room. Yes, the look similar. The reason I bought 4 bottles is that the bottle of water costs 4 USD in the hotel where you can buy it from outside with 2.25 USD. I bought 4 in the first day of staying in the hotel because I have to stay hydrated (medical reason).
The guy finally said I'll let the manager talk to you.
After 20 minutes the manager called. She said:
Ok, we removed that extra charge on your room but "next time if you used that bottle we will charge you $ 4"
I replied: do you mean that I used that bottle of what?
She replied: I'm just telling you its for your information.
That was very rude and so offensive from hotel management. She said "next time" - that means "yes, you used that bottle and now we removed that extra charge and if you do that next time we're gonna charge you". I swear that was so sick and I have never received such insultation from a hotel personel in my life. I stayed in a lot of hotels and resorts in my life and none of them gave me such experience. I never bothered writing about any hotel but I'm doing that now just to let hotel management know about it (that if they care).
I was here also Dec last year and the place is really below average I can say. The house keeping doesn't clean the room, the come and tide up the bed and replace the towels, clean the bins and leave. one day I intentially left some chips on the rug and no body cared to clean it. Sometimes they miss extra towels and the other day the set is complete. Someday they take bath mat with them and other day they bring it and now my room without it. Don't know if they are going to accuse me of stealing it or not.
I wish I have extra time to write about this misrable hotel but I don't.