It sucks, and for the one fact I like trolling, and it usually goes something like this.
noob: bla bla something stupid about something obvious
me: <answering>
me: <trolling like a pro, with something inteligent, or just plain rude, depends on my mood>
me: <punchline, to make everybody giggle.>
A joke isn't a joke without a punchline. it's like ending it after 'knock knock'.