I think one key part of a child’s development is learning to interact with adults on an adult level. There are some extroverted kids who do not hesitate to approach adults, but my kids are not like that. In fact, it is rare that I meet kids under 10 years old who are good conversationalists (in fact, I find few adults who are good but that is another story). That is why I try to encourage my kids to handle their own affairs as much as possible.
They get allowance and so if they want to buy something, I ask them to stand in line at the cashier and buy it themselves. Want a mango Slurpee, the check out line is right over there. I think that in addition to developing their social skills, asking them to make the purchase also forces them to hesitate a beat longer to think about how badly they want the item in question.
Beyond that, I think you can learn something about your children and how they conduct themselves around strangers. I think putting kids outside their comfort zone will make life a little easier for them when they find themselves in a pressure situation on the athletic field or having to give a class presentation. I remember once when my oldest son was 9 year old his football coach asked to take him to a town parade while the rest of us went to my daughter’s soccer game. The coach pulled up in a black corvette and picked up my son. The two spent several hours together and when it was all done, the coach said to me, “Hanging out with him is like hanging out with my buddies, but he is only nine.” It should be no surprise that my son and that coach developed a close bond as a result and the two worked together on the football field calling plays and running the offense in a way that adult coaches and 9 year old players rarely do.