When asked to try and recover data on a very sick HDD.
Buy a new one, I'll fit it as the m"aster and see what we can get off of the old one" (set as a slave) was the instructions.
The guy (who I hardly knew) sent his wife out the next day for a new HDD. That evening I turned up to fit it and got a right ear-bashing off of her because it had cost her 80 quid!
I recovered all his data, was promised a bottle of whiskey (which never arrived) and I've never seen him since!
Stopped doing it then.
Oh, did I mention the data that I recovered was his business account, VAT, wages etc. for the last 18 months!! Just a pair of ear defenders would have been nice but in their absence I've learned to say "NO!"
I've set up two PC in the last 18 months for friends of friends of relatives.
Getting the PC up and running hasn't been a problem. It's the training that the people then expect you to give them afterwards that is the real pain.
I spent over 30 hours showing somebody how to do just about everything; including switching the PC on and off, connecting to the internet, downloading a firewall and anti-virus program, then showing them how to use Word and all the other programs that came free with the PC.
And if the slightest thing goes wrong, they expect you to sort it out for them. Aaaarrrgghhh.