I hear what you're saying. Experiences definitely can reinforce our negative thinking. I consider myself realistic in the sense that I weigh things more than others, and decide based on the most probable outcome given my current state, but guess what? I'm the least to enjoy life this way. Is it because I'm realistic? Probably, because I'm not taking the risks to challenge my thoughts and change my current state. Eventually, we cannot know for sure how things will play out, and how that could change us. For example, I suffer from social anxiety, so, what is the most probable outcome in a social situation? It would be that I would be nervous and anxious. So, I decide most of the time to avoid social settings. Is that realistic? I think so, given my current state of social phobia. Is being realistic helpful for me? I don't think so, because it contributes to my isolation, loneliness, and eventually depression. Getting out of your comfort zone is the hardest thing to do.