I have a young baby - so far from an expert - but just can't believe some of the things that were said/done to me with my newborn.
I'm going to see my friends baby and will make sure I don't come out with any stupid comments although I probably will!
So let me know your corkers! 
Here are a few of mine (think week old baby):
(sitting down on sofa) Mines tea with two - not too strong mind
(Flicking through diary) - so when are we going on the piss?
(young family member) - so do you think you'll EVER wear make-up again?
So when are you going back to work?
So when do you think you'll have another?
Oh I can sympathise with the lack of sleep - our neighbours car alarm went off again at 5am!
Enjoy this time - they just get more demanding (do NOT need to hear this now thanks)
Now remember what we said about resting and saying no to visitors - same time again tomorrow?
(when baby turns head to visitors chest) ooh I'm sorry, no milk in there! (wrong, wrong wrong!)
(After spending two hours feeding and settling baby) So, shall we take baby out now so you can get on with some ironing? (aaaaaaaaahhhh! and bring baby back screaming and ready for next feed? Can't wait!) 
(Every 5 minutes) Yes, it's wind. Must be wind. Have you got wind baby? Aw nasty wind!
I never slept when baby slept - it just makes you feel like a lazy slob doesn't it?
It's amazing how you just forget the birth isnt it? No. I'm scarred for life. Literally.
I think I can laugh now... just. 