When it comes to Family Guy, there is no shortage of annoying characters. In fact, every character is annoying in some way or another. But there are some characters who are nothing BUT annoying and one of those is Neil Goldman. Neil is voiced by Seth Green and is a stereotypically nerdy kid, serving on the newspaper team as well as the A/V club.
Plenty of characters from Family Guy come back from the dead, and Joe and Bonnie's son Kevin is one of them. Kevin supposedly died in the Iraq War, but he returned to the show after surviving a coma and faking his own death. He continues to live with his parents and has attempted suicide at least once, and Meg, of course, has a crush on him. He's pretty much the only character to be nice to her on the show (aside from Neil).
You may know him as The Giant Chicken, but the resident poultry pest in Quahog is named none other than... Ernie. Ernie is a running joke in Family Guy, as he always gets into a brutal fight with Peter until the two are bloody and bruised. Peter always wins and leaves Ernie for dead, but Ernie always awakens and, like a bad scary movie, seeks out his revenge again later. It's always completely random and out of the blue, and Peter returns to what he's doing each time as if it never happened.
He has a token name to go with the token Black character on Family Guy, but Cleveland Brown is one of the most underrated characters on the show. Sure, he got his own spinoff, but on the show itself he doesn't get the limelight nearly as much as Joe or Quagmire, yet he's one of the more likeable of Peter's friends. Cleveland is definitely the most introspective of the quartet of Quahog men, often pointing out an obvious truth that the rest of the characters just don't get.
Glenn Quagmire is the character that plenty of Family Guy fans love to hate. He's by far Peter's worst friend, and while he can have a heart sometimes, most of the time he's pretty much the worst. Depraved, irreverent and downright inappropriately perverted at times, Quagmire is the favorite character of people for the same reason Cartman of South Park is a favorite. He's the id, amped up on steroids, let loose in a fictional cartoon town.