Quagmire was a funny little novelty when I first began watching Family Guy somewhere around season 2. One of his funnier moments is in an episode where he's seen standing my his window, naked, and then the window falls down and crushes his penis. That was pretty funny. But just like everything about Family Guy, it stopped being funny and just began to become this long, drawn out joke that at any party you'd just start to ignore and walk away from when that one drunk guy won't stop shouting "That's what she said" every time someone else said "so I was making love with my significant other".
tl;dr boomhauer.