[robertphil]

now and then i say yes to a job but then later i want to change my mind-get out of starting doing it for variety of reasons,(sense a bad payer, sense a nitpicker, jobs a tad awkward "a hater" ,bad  access  etc )   but i want to get rid without causing fuss ,without losing face .
 so far i have mainly relied on the blown van engine excuse but its not a good un

anybody got any good excuses ?

[Ben wood]

Yeah use
Sorry i cant clean your window because i think your a snotty nosed, winging old bag and i dont bloody like you.

Let me know how you get on, if it works for you i will try it 

[4S Cleaning]

Should clean it once, say more work than i thought & put the price up, if they go for the price then it might be worth the hassle  if they don't then your off the hook

[richardlingard]

just dont go back :-)

put the price up via letter

[Londoner]

I clipped a few customers in one road that I didn't want to do anymore by telling them I was having to reduce my round because I was getting RSI in my wrists.

[andyM]

Put the word out that you have got to do "a bit of bird" for stealing a customers knickers off their washing line. 
 

[Elfyn]

In the words of Paul Simon.
"slip out the back Jack
  Make a new plan Sam
  No need to be coy Roy
  Just set yourself free"
And there's more (50, in fact)
 
http://www.youtube.com/watch?v=RTiyLuZOs1A

[Ian101]

perhaps you could just tell them ??

mind you there have been a few Ive just not gone back to in my early days but just tell them these days as Im an old hand after 2 1/2 years ... all bitter and cynical