Anxiety is our ability to predict danger and warn us about it. It gives us the opportunity to look into the future, anticipate problems, and take corrective action now in order to prevent bad outcomes.
For example, consider being worried about looking stupid at a party, or being afraid of failing a test, or being rejected in a job interview. All of these things are examples of our mind looking into the future, analyzing the situation, and warning us about danger so we can do something about it.
Sometimes people say that they have anxiety over the past. But if we tunnel down into that even then, anxiety is the anticipation of future consequences of a past action.
For example, one might say “I’m anxious about what I said at the party last night.” While that looks like a past-facing statement, it’s actually the underlying worry of what people WILL think about what this person said at the part earlier. Its the anticipation of what will happen as a result that causes anxiety.
Moreover, the smarter you are, the worse your anxiety will be. The more that your mind can compute potential futures, the more potential problems your mind will tell you to worry about.