I have used Freecycle for a while now, and have given lots of stuff away and received stuff without any problems...until now.
I responded to an offer of a deep freeze, as we needed a spare one for the garage. It was listed as 'working condition', so I wasn't expecting it to be pristine - I thought maybe dents, scratches etc but fine for the garage.
So, DH and I went round to the people's garage to collect it. Words cannot describe what a disgusting state it was in. As I said, I didn't expect something given away free to be great but this was filthy - covered in mould, and really dirty inside - bits of food everywhere. It also smelt like something had crawled in several years ago and died. There had clearly been no effort at all to clean it - not even a quick squirt and wipe with Dettol.
At that stage, DH and I were too embarassed (and shocked) to say 'thanks, but no thanks..' so ended up taking it home. It's now sitting in our garage, until I pluck up the courage to go and deal with it. TBH, I am considering just taking it to the tip.
Normally when I collect something from someone on Freecycle, I send a nice thank you email telling them how the item has been put to good use etc. In this case, I can't bring myself to do that (am even tempted to complain to them or to Freecycle - but DH thinks that would be OTT).
Again, I stress that I understand the item was free BUT... surely the point of the site is to pass on your unused items to someone else, not to dump your filthy junk to save yourself a trip to the tip.
Just to give an example...I Freecycled DC's baby clothes recently - several binbags' worth. They weren't in great condition (some already 2nd hand when I got them) but perfectly usable and washed. I could have just been bone-idle and not bothered to wash them, just passed them on with puke/poo stains etc. But I wouldn't do that, just out of common decency - obviously what these people lack!
And....breathe.
SO - AIBU to not thank them? WIBU to complain?
(Suspect the latter is a definite 'yes' 
)