The 3 Second Rule is guideline that many PUAs follow to overcome approach anxiety. Hesitating too much before an approach can lead to overthinking and nervousness. It can also creep a set out if she notices you staring at her for too long. Opening a set within three seconds allows you to “be in the moment.” Following the 3 Second Rule also doesn’t allow you time to come up with excuses for not approaching the set.
This is a counter rule that goes hand-in-hand with Mystery’s 3 minute rule during set selection. Mystery advocates that you should not approach any sets that might get interrupted within 3 minutes of speaking with her. Again, these rules are developed as “guidelines” to help PUAs do the best sets and do not always have to be followed.
Generally though, coaches advocate the 3 second rule when entering new venues, talking to the first set they see.