My 4yo daughter is well-behaved and polite, but not shy and does have impulse control hiccups at home sometimes.
When she receives a compliment she says thank you. I have had people gush about her behavior, which is ridiculous because I believe that most children 4+ have it in them and should be well-behaved. It's hard work (diligence actually) but it is our jobs as parents to raise functioning citizens. Don't get me started! Anyone who criticizes well-behaved children needs help.
Danielle, Nick, Gigi ('08) and William ('11)