I can't recommend being intentionally rude so that you can get practice dealing with people who are pissed off at you. Learning how to tell when it's a bad time to strike up a conversation with a stranger will be a much greater benefit for anyone looking to meet women or even for someone just working on being friendlier/more social. There'll be no shortage of opportunities to learn how to deal with rejection even without being a pest.

I cannot agree with that. Do not be shy about trying, but do not be a pest either. There are many times when interruptions are not good for both sides. My 2c.