A meme sweeping the web has a new entry courtesy of workmen in Chester who painted a warning sign on a road outside a school that was knocked down four years ago. "You had one job!" residents might have shouted at the men painting the "school" zigzag sign, using a phrase that has been added in bold font to photographic evidence of haplessness across the internet.
Other cock-ups documented online include misspelt signs ("Stop" appears to be particularly challenging), a T-shirt with "Asia" in large letters below an outline of Africa, trees planted in parking bays, a race medal showing "3st" place, on/on switches, and various supermarket labelling snafus.
According to knowyourmeme.com, the earliest mention was in Ocean's Eleven (2001) when Don Cheadle's character berates his team for messing up a vault heist: "You tossers! You had one job to do!"