Our minds use paradigms to filter all sensory input. Your mind used a paradigm, a set of rules, to filter out the noise and process only the voice of your friend. That's a tough question. The trick is realizing that you are basing your decisions on a paradigm and then find a way to see around it. If you make a decision based on instinct or feeling without examining the evidence, you probably based that decision on a paradigm.
Any snap decision is based on a paradigm.
When your decision goes against the evidence at hand you are basing it on a paradigm. That is not to say these choices are wrong or bad. They may be absolutely correct. If our paradigms always led us astray we would have become extinct a long time ago. There is no sure way to see around your paradigms.