We all have a degree of pessimistic tendencies (some more than others). While it's sometimes useful to expect bad things to happen, ask yourself one question to avoid going overboard: What's the cost of being wrong?
Neither pessimism nor optimism are inherently good or suited for all situations. How can you distinguish between when it's appropriate to assume the worst, and when it's OK to have a little hope? Author Martin E. Seligman suggests asking "What's the worst that could happen?" as a filter for your pessimism:
The fundamental guideline for not deploying optimism is to ask what the cost of failure is in the particular situation. If the cost of failure is high, optimism is the wrong strategy. The pilot in the cockpit deciding whether to de-ice the plane one more time, the partygoer deciding whether to drive home after drinking, the frustrated spouse deciding whether to start an affair that, should it come to light, would break up the marriage should not use optimism. Here the costs of failure are, respectively, death, an auto accident, and a divorce. Using techniques that minimize those costs is inappropriate. On the other hand, if the cost of failure is low, use optimism.
Of course, the cost of failure is not only subjective, but can even be influenced by optimism -- in the affair example, one might convince themselves that cheating would make them happier, even if it would actually cause more problems. However, the mere act of asking the question can help identify when it matters and when you can just let it go.
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