But there’s nothing wrong with optimism! Either the vaccine is ready, or we set a new deadline.
The doom and gloom and pessimism doesn’t get anyone any further towards hope of happiness!
I'm not sure it's about optimism vs pessimism.
I think it's those who want to temper their expectations and maybe be pleasantly surprised, vs those who are quite optimistic, but get disappointed every other month. In March the optimists were suggesting 6 months, the realists were suggesting 18 months, maybe a little quicker. The optimists, come September, are almost certainly going to be sorely disappointed.