Sometimes, we don't want to overcome the setback, and we don't want to get beyond the pain.

In present day society, we only want to feel happy, so why should we plan for negative events or sadness? Because of "positive psychology," we don't want to think about "setbacks" or troubles that threaten our progress. When a setback happens, we often find it hard to adjust. We don't know that negative thinking is normal, so some of us fall into patterns of negative behavior or guilty feelings. We ask, "Why this? Why me? Why now?" Yet, to some extent, we made a mistake in judgment, so we have only ourselves to blame.

Negative thinking protects us from harm, and negative experiences provide opportunities to learn. The best we can do is go with the flow, learn from our mistakes, and try to overcome any setbacks. But sometimes, we don't want to overcome the setback, and we don't want to get beyond the pain. Instead, we want to hold on to our misery, replay it all in our heads, and watch the sadness build up. 

The brain tends to provide more of what we expect, so if negative thoughts are feeding the brain, the brain begins to feed the negativity. This becomes a cycle of sadness creating more sadness. This is how depression starts, how it grows, and how it continues to live until it becomes overwhelming. That's when negative thinking can lead to depression and increase the risk of suicide. 

Negative thinking is important if you want to take some time to determine what happened to cause your misery. That way, you can give yourself a "reality check" to determine which of your negative thoughts are exaggerated or which are just wrong. This allows you to adjust your thinking and exchange the negative self-assessments for more positive ones. As long as you don't spend too much time reliving negative events, some negative thinking can be helpful.

Negative thinking is normal (at least for a couple of weeks or so) but incessant, overwhelming negative thinking creates sadness. If negative thinking controls your thinking during the day for weeks at a time, this might be a sign of depression, which requires a doctor's opinion and possible intervention.