Be honest, use proper grammar and avoid slang and expletives.
Although names of friends, expletives, and the like may be legal according to the other rules, they do absolutely nothing to improve the readability of your programs.
A lot of circles and squares were drawn on the board, arrows and acronyms abounded, and more expletives — of enthusiasm this time — were uttered by all.
A more populist outfit is Public Matters, led by Radek John, an investigative journalist who shuns suits and peppers his stump speeches with expletives.
'It was scary. I was terrified. I'm not ashamed to say I screamed and uttered a few expletives.'
Previous studies have shown that letting fly with a few choice expletives can ease pain.