The glass analogy is not helpful. A half-full glass might even threaten your life.
Talk about optimism and most people will think of the glass analogy. But what does having a half-full glass really mean?
Is it really optimism - or denial?
For some, it means never facing reality. They won’t go to their doctor to check out a lump, because 'everything will be okay'. Other avoiders believe that going for a health check would suggest they are not optimistic (and they know that successful people are always optimistic).
One irrational optimist once told me he doesn't take out insurance because that would suggest he was expecting to claim, 'and that's a really pessimistic way to look at life'.
Rational optimism and being realistic
For rational optimists, having a glass half-full suggests they believe that, generally speaking, life will work out okay. That general sense of optimism is healthy.
Rational optimists do focus on the positive, but it doesn't stop them facing reality. It doesn't stop them being pessimistic from time-to-time.
Rational pessimism works too
Being pessimistic about achieving a goal, then developing strategies to overcome the hurdles that might arise is a very effective strategy.
Rational optimism is an outstanding characteristic of top performers in any field you care to name.
Finding the balance of rational optimism and rational pessimism is what counts. The half-full glass is too superficial to be useful.