Either way, optimism and pessimism cannot work at the same time now say if someone is an optimist, they can still have some negative thoughts but they are obviously not negative most of the time which is a pessimist. So my answer is no, they cannot be harmonious in one entity.Click to see full answer. In this manner, what do you call a person who is optimistic and pessimistic?Optimistic, Pessimistic, or Realistic. Optimism is when a person is more likely to look at the positives in a situation. They are commonly found saying things like “it could have been worse” and “well at least…”. Pessimism is when a person is more likely to look at the negatives in a situation.Subsequently, question is, what is the definition of optimistic and pessimistic? optimistic/ pessimistic An optimistic person expects all the best things to happen! A pessimistic person is a downer. Subsequently, one may also ask, what is a pessimistic person like? A pessimistic person is a downer. To be pessimistic means you believe evil outweighs the good and that bad things are more likely to happen. So pessimistic people are usually pretty negative. And kind of a bummer to be around.What do you call a person who is always positive?optimistic. An optimistic person thinks the best possible thing will happen, and hopes for it even if it’s not likely. Someone who’s a tad too confident this way is also sometimes called optimistic.