Bad Thing n.
[very common; from the 1930 Sellar & Yeatman parody "1066
And All That"] Something that can't possibly result in
improvement of the subject. This term is always capitalized, as
in "Replacing all of the 9600-baud modems with bicycle couriers
would be a Bad Thing". Oppose Good
Thing. British correspondents confirm that Bad Thing and Good Thing (and prob. therefore Right Thing and Wrong Thing) come from the book
referenced in the etymology, which discusses rulers who were Good
Kings but Bad Things. This has apparently created a mainstream
idiom on the British side of the pond. It is very common among
American hackers, but not in mainstream usage here. Compare Bad and Wrong.