We have, of course, been trying (and trying) to teach LR manners over the course of his short life. This recently bore surprising fruit.
I was on the phone and LR came in from the other room. He walked right over, said "Excuse me Daddy," and then stood there waiting for me to acknowledge him. For a moment I was a bit stunned, because this occurrence was about as likely as Bill O'Reilly moving to Massachusetts and marrying Barney Frank. Once I collected my thoughts I asked my friend to hold on and said "Thank you very much for saying 'excuse me,' what can I do for you sweetheart?" Surprisingly, he had already turned around and was halfway out of the room by the time I asked him this. I tried again. "LR, did you want something?" He turned and said "No. I burped in the other room so I came in to say 'excuse me.'"
It may not be what I expected, but I'll take whatever I can get.