Forgetful,
silly.
Born in 1978, Hilversum, The Netherlands. First used by UK-
based employees of Philips Telecommunications (employed at Malmesbury in Wiltshire, UK).
On a business trip to Philips Telecommunications headquarters, some time between
January and April 1978, a colleague of mine arrived in his hotel in Hilversum (The Hilvershof), unpacked his suitcase and found he'd left his briefcase at home. Looking around the hotel room, he located a suitable plastic bag and proceeded to use this to carry
work-related items to and from
work for the duration of his trip.
The bag bore the legend "waszak" - the Dutch word(
s) for "laundry bag". Henceforth, anyone doing anything thoughtless was called "waszak" and a new word entered the English language.