Phrase for "Thinking that something is not going to happen, then act in a way that causes that thing not to happen"? [closed]
It's on the tip of my tongue -- I want to refer to a person who believes that A is not going to happen, and therefore acts in a way that ends up preventing A from happening.
Self-fulfilling prophecy I believe is what you're looking for!
Or, if you're thinking of it more intentionally, maybe self-sabotage(-ing)?