Well done, TheStumbler! Although you may be frustrated with what you didn't do, you did care enough for two strangers to help them critically think for themselves instead of being victimized by the WTBTS.
I personally wish that I was better at controlling my emotions, asking more questions that peaks a JW's curiousity, having pre-planned how to overcome the WTBTS's thought-stopping platitudes, encouraging JWs to do research about a specific topic of disccussion, and inviting them back to converse more. I have learned from experience that I need to practise a lot more. I wish that the WTBTS would set-up literature carts near me, so that I could practise more.
Peace be with you and everyone, who you love,
Robert