I am an introvert, but I have my extroverted moments. Remember that there is in everyone a bit of their opposite temperament. I am no exception.
Sometimes my extroverted moments do come naturally, I swear. At other times I need to manufacture such moments. There is a limit of course, because despite what anybody tells you, true introverts cannot become extroverts. Yet there are certain extroverted actions I can opt to take if the need arises. (And provided I have a few days to recover afterwards.)
In order to initiate such extroverted moments however, I have to remind myself that not everyone is an introvert. This may be the hardest part about me being extroverted at times, even when it is acceptable and possible for me.
You see, in most situations I would prefer not to be approached by a stranger on the street. And as I go about my day I let myself assume that nobody else wants to be approached either. As a matter of fairness I say to myself, "Now if you were sitting on that park bench you would not want a stranger to come up to you and ask you a question. And even if you wouldn't mind, you owe it to a stranger to be extra careful about taking up their time. You therefore have no right to walk up to a stranger yourself and ask a question, even during the rare occasions when you find the need."
The truth is even I do not always hate being asked something. But I give an even greater bubble to other people than I expect of myself, because my immediate thought is to leave everyone alone at all times. After all, I usually want to be left alone too.
As an introvert, I believe that everyone deserves to be left alone. And for the most part I do leave everyone alone. But there have been times where it would have been in my best interest to engage someone, but I didn't, out of a heightened sense of propriety.
Just as extroverts tend to assume that anybody sitting alone would welcome their company and conversation, we introverts tend to assume that they would not. Sometimes we are correct, and sometimes we are mistaken.
So the key to me is to prioritize. If as an introvert you have determined your reasons for doing an extroverted thing are legitimate and likely to be of benefit to you, go on and do the thing you are considering, (assuming of course you are comfortable with it.) If the person wants to be left alone, you of all people can understand that. And if they do not mind engaging you, than you can be surprised, and receive whatever benefit you were hoping for in the first place.