Two columns, not one
When choosing between project ideas, put observations in one column and assumptions in another. “Three people requested this feature” is an observation; “everyone needs it” is a broader assumption.
Ask what could change your mind
For each option, write evidence that would make you reconsider. Design a small test that could reveal it. If every possible result supports the same choice, revisit your question.
Record, then revisit
Record the decision, date and main reason. Set a review point and compare expectations with what happened. The aim is to learn from the decision, not produce a psychological score.