HAPPINESS is a tricky thing. "Is it wrong not to always be glad?," trilled Morrissey in The Smiths' "Sheila Take a Bow". He might well ask, having made a career out of being magnificently fed up. Imagine 'Heaven Knows I'm Miserable Now' if he wasn't? 'Blimey, I'm Rather Chirpy' doesn't have the same ring.

According to a great book I'm reading on the subject ('Happiness: Lessons from a New Science by Richard Layard') the feeling of happiness can be measured. Apparently the left side of the brain responds to nice sensations and the right one to unpleasant experiences, which at least explains the lopsided headache you get while watching You've Been Framed.

I've got my own theories. There are a few easy ways to tell if you are a happy person or not. Is your glass half empty? Is it half full? Or is it lying in broken shards on the floor while you crawl weeping on your hands and knees over it?

It is important to remember that no-one can make you unhappy (Not even Pauline from Eastenders). No-one can make you feel anger, except yourself - so remember that next time your brother in law is prodding you repeatedly in the head with his dinner fork. Then again, if you slap him in the chops and it angers him, you can lay the blame firmly at his door.

The good news is that routes to happiness can be found almost everywhere you look. You can buy a good book. You can spend time becoming a rounded human being. But be warned, things that look like a short path to happiness can often to be the road to hell. And that includes the purchase of a Chris Rea CD.

Some people spent their whole lives working to earn money to be happy through the acquisition of big cars, expensive holidays and nice jewellery, then realise aged 60 that they would have been just as content with a pasty and a nice sit down in front of the telly. If only someone had told them sooner.

People who are happy often have the misfortune to be born with an unhappy face, inviting frequent cries of "Cheer up, it might never happen". This tends to cause the exact opposite scenario - a fixed grin when inside, they're murderous.

There is good news for happy people: they are healthier than the rest and will probably live longer. A fact which has probably just trimmed another 10 minutes of life expectancy off the more disgruntled readers.

Some people are never happier than when they are in the midst of a big bout of trauma, and secretly fear that, if happy, they would be unspeakably dull. Friends don't like to point out that while this might be true it would, at least, be one step up from pathological cheerlessness.

Still, unhappiness has its place, given that it is hard to be happy without having been unhappy in the first place. How would you know the difference? One last note on happiness - you can have everything taken away from you, but no-one can take away the freedom to choose your attitude. Which is why when anyone tells you that you're a miserable blighter, you should reply "Yes. And I'm really happy about it, thanks."