Old Man Trouble

If you know what's good for you, you definitely don't mind him (says Susan Sto Helit). In Thief of Time, Susan notes that she's met Old Man Trouble, and later warns Lobsang Ludd not to run into him (since Lobsang doesn't have rhythm, music, nor the girl).

Comes round your door if you ain't got rhythm and you ain't got music. It's best if you don't mind him. Mentioned in Soul Music and Hogfather as one of the gods who, having lost his purpose, has truly gone insane. Also mentioned as being in Biers (a bar in Ankh-Morpork) in Feet of Clay.

He wears a long mac and a wide brimmed hat that shadows his face so that all that can be seen of him is his two dreadful glowing eyes. In The Discworld Companion he is described as the anthropomorphic personification of Murphy's Law, the general intractability of the universe and the darkness in the cellar.

In Hogfather, Lord Downey notes (to the Auditors of Reality) that he's unlikely to attract the attention of Old Man Trouble, since he can carry a tune quite well.

Annotation

A reference to the George and Ira Gershwin tune I Got Rhythm:

I got rhythm
I got music
I got my girl
Who could ask for anything more

I got good times
No more bad times
I got my girl
Who could ask for anything more
Old man trouble (old man trouble)
I don't mind him (I don't mind him)
You won't find him
"Round my door"

I got starlight (I got starlight)
I got sweet dreams (I got sweet dreams)
I got my girl
Who could ask for
Who could ask for more

He wears a long mac and a wide brimmed hat that shadows his face so that all that can be seen of him is his too dreadful glowing eyes. In those parts of Roundworld where the Vikings once were, this is the classical manifestation of the great god Odin/Wotan/Weyland among men, and nothing good ever came of a chance meeting with a stranger on the road answering this description. --AgProv 10:15, 5 February 2009 (UTC)

According to Mikko Kuusiriti in Discword Monthly, Old Man Trouble is thought to be the devil, but a more down to earth version (think of George Spiggott [Peter Cook] in Bedazzled) He is a sadist who takes a pride in things going wrong. A number of things going wrong used to mean a visit from Old Man Trouble.