I can appreciate why there is a huge fanbase towards Family Guy - the very fast pacing of joke-joke-joke means there isn't time to dwell on the ones that fall flat or are even offensive. And having watched a few episodes myself in the past, there are some individual moments I found really entertaining, funny, witty or even nostalgic (like when Chris ended up in a Take On Me parody, or Stewie rides the '1-2-3-4-5!' pinball machine that I hadn't seen since my days of watching Sesame Street) albeit in an off-colour or dark fashion.
That said though, it's a very thin tightrope Family Guy balances on and all too often for me personally, the jokes are either so heavily-dependent on American pop culture (which is a nightmare for an outsider like me in the UK if the episode is political), or fall flat (because I personally find it too mean-spirited, juvenile or just out-and-out weird), or just plain aren't funny (usually whenever Brian or Stewie have episodes entirely dedicated to them dating or what have you) that I've given up on Family Guy altogether. Maybe Seth McFarland stretched himself far too thin with American Dad (moving to Time Warner I heard), the now-cancelled Cleveland Show, Ted (second movie in production), and the no-one's-sure-what's-happening-with-it Flintstones revival..., so the flaws in his original project are progressively worsening without his attention, or Family Guy has outstayed its welcome? Shame really as the animation's gotten better in recent years.
At any rate, Family Guy is just one of those things like Marmite - people either strongly love it or hate it. As long as the series keeps making money, FOX (or Comedy Central or whoever commissions it there) now, will keep going with it regardless of online consensuses. I'm just glad I saw it when I did.