Invest in people proportionate to your expected return. Your prior on returns should be very low, most people are a waste of time and resources (Specifically for this particular example, your investment was your emotional reactance to things they do). Low but still positive, so you invest a tiny bit and watch what happens. If you actually get some returns great! Repeat with a slightly larger investment. Otherwise start with a new person.

Your anger is understandable, things are more frustrating when they are close to awesome but then fail in a stupid way than things that were never awesome. These "almost awesome" things give you a glimpse of something amazing before snatching it away. Even though our platonic awesome thing never really existed we still feel loss.