I think threads like this are very good for us to clarify in our own minds how we feel about our childs abilities. Often, our children can't distinguish when we are pleased with something, or proud of something. We have to know how to express our feelings in words to benefit our children and to respond to others.

I like responding with, "I'm pleased the school has provided opportunities for a great education."
Or, "I'm proud of you for making a good choice, treating someone kindly, working hard, etc."

And DeHe, 4 year olds are allowed to say those kinds of things! When someone comments, just laugh and say there's never a dull moment at your house! Your child will know you accept him as he is, and the stranger will agree with you.