In 1990’s Scotland there was a great series of TV adverts designed to reinforce our recall of the Tennent’s lager brand by judicious use of words ending in their big red capital T. Younger readers may also be familiar with the summer festival T in the Park, which does exactly the same thing.

Anyway, these ads featured the pouring of half of a glass of Tennent’s in front of someone, who either laughed with joy or cried with sadness, depending on whether they were an glass-half-full optimisT or a glass-half-empty pessimisT.

These days we’re under increasing pressure – perhaps it’s our gradual Americanisation – to be incorrigibly upbeat and optimistic about everything. Our positive outlook alone will affect the outcome. It’s the positive spin we put on life and especially in marketing. This is true in parts. I’ve always described myself as a realist, occupying the halfway house, a hope-for-the-best-plan-for-the-worst space in between the two characteristics.

The other day I was chatting to my son who can sometimes be sweepingly downbeat in that glum teenagerish way. I told him he was sounding like a pessimist. ‘I’m not a pessimist Dad,’ he countered, ‘I’m a non-delusional realist.’

Which opens up a whole new can of worms. Is that the same thing as a pessimist, or is it a qualification of a realist, or is it suggesting there are many shades on the pessimist-optimist spectrum, or many grades to the axis?

I know, thinking too much…