There was a good education on how not to do self-build on Homes under the Hammer this morning.
It is the first example in this programme, and about 20 minutes in for the outcome.
http://www.bbc.co.uk/programmes/b08ny6bx
My favourite:
'I photographed all the noggins, and then deleted all the photos. Then when my plumber asked where my noggins were, they were harder to find."
And a lot more.
To be fair, they just about broke even ignoring their own time, and plan another one.