Your notation sucks

Obviously I don't need to tell you about the blog war that is currently in progress between Tim Ireland and Guido Fawkes. I have nothing to say on the matter, I'm just enjoying the bun fight.

However, via a link in a comment on one of the posts, I came across this wonderful anecdote about the mathematician Serge Lang:

When attending others' math lectures, he was not reticent about telling the lecturer "your notation sucks"; this trait was reliable enough that he was successfully goaded into saying it at a lecture where he was then presented with a T-shirt bearing this phrase.

The offending notation, pronounced "Xi over Xi-bar", is written:

`Xi / bar(Xi)`

The usual caveats about the reliability of Wikipedia apply. By the way, getting that formula to come out properly requires a java-script, so it won't work from an RSS reader.