Bloody marvellous film, and a perfect counter-example for anyone who claims Hollywood only mass-produces rubish. Yes there are plenty of silly, smutty lines which you could cite as evidence of immaturity (e.g. our hero in a club having bottled chatting up our heroine, justifying himself to his friend: "Ah, I'll just jack it off later") ... but even these are sharp and delivered fast, almost thrown away, which I find quite classy.
My favourite line wasn't actually a funny one. It was the brother-in-law of our heroine, father of two: "I wish I loved anything in life as much as my kids love bubbles." There were loads of acute observations on parenthood and ... er ... beards, and it was fantastic.