The rule is: the word 'it's' (with apostrophe) stands for 'it is' or 'it has'. If the word does not stand for 'it is' or 'it has' then what you require is 'its'. This is extremely easy to grasp. Getting your itses mixed up is the greatest solecism in the world of punctuation. No matter that you have a PhD and have read all of Henry James twice. If you still persist in writing, 'Good food at it's best', you deserve to be struck by lightning, hacked up on the spot and buried in an unmarked grave.

I recently heard of someone studying the ellipsis (or three dots) for a PhD. And, I have to say, I was horrified. The ellipsis is the black hole of the punctuation universe, surely, into which no right-minded person would willingly be sucked, for three years, with no guarantee of a job at the end.

Sticklers never read a book without a pencil at hand, to correct the typographical errors. In short, we are unattractive know-all obsessives who get things out of proportion and are in continual peril of being disowned by our exasperated families.

Texting is a supremely secretive medium of communication - it's like passing a note - and this means we should be very careful what we use it for.

You don't want to make an enemy of Piers Morgan.

Well, start waving and yelling, because it is the so-called Oxford comma and it is a lot more dangerous than its exclusive, ivory-tower moniker might suggest. There are people who embrace the Oxford comma and people who don't, and I'll just say this: never get between these people when drink has been taken. Oh, the Oxford comma. Here, in case you don't know what it is yet, is the perennial example, as espoused by Harold Ross: "The flag is red, white, and blue." So what do you think of it? Are you for or against it? Do you hover in between?

Panda. Large black-and-white bear-like mammal, native to China. Eats, shoots and leaves.