Him: "So tell me Mr Guitar Guru who decided on the number of strings and the plucking thing and such?"
Me: "Hehe, erm... I don't know who invented the guitar actually. There's six strings... as you go up the fretboard you make the pitch higher. So like, each fret is a different note."
Him: "What are chords then?"
Me: "I think it's 3 or more notes played at the same time."
Him: "Ahhh so how many chords can you play in a second?"
Me: "Ermm... probably 2 or something, you don't usually change chords that quickly, it's lead guitar when people play fast with loads of notes and that."
Him: "What songs can you play then? Can you play Hey Jude?"
Me: "Can't remember the chords off the top of my head but I think it's quite simple... probably yeah."
Him: "Ah see I am aware of SOME Beatles songs! I'm not completely out of touch."
Me: "Heheh..."
Me: "He sort've wrote that for John Lennon's son Julian I think. But changed it to Jude. Cos it sounds better, probably."
Him: "Did he? That's odd."
Him: "So Oasis knew John Lennon?"
Me: "What?"
...
Me: "No John Lennon was in The Beatles wasn't he."
Him: "Was he?"
Me: "Yeah"
Him: "Has he got a brother?"
Me: "...not sure. Are you thinking of the Gallaghers? :D"
Him: "Don't know...is John Lennon still alive?"

tl;dr