Characters: don't overdo it.

Yesterday, I had an exchange with a friend on Facebook. I spoke about one of my characters in the Thriller. Gary O'Neil is a 20-year-old Irish bloke, shy, fair-skinned, has red hair and freckles and works in IT. He gets red ears, either when embarrassed or excited.
My friend said he's too much of a stereotype. I agree on the stereotype, but not on the too much. My friend suggested I'd make him mixed raced, and more off the wall, but I declined. The reason being is that he's a minor character and he introduced himself being like he is. But he has an exciting and rather unexpected hobby :parachute jumping and goes to the gym to keep his neck and back fit for that.

All my main characters are normal people, like your neighbour next door, that's what I've been told I'm good at: create real and believable characters with their ticks, their angst, their thoughts and I believe that Gary is as believable as all other characters in the book. I find it not necessary to create characters as much off the wall as possible. Maybe in Sci-fi or Fantasy, but not for a Thriller. I do have Sarah, though, tattooed and pierced, a bit on the tough side and people would expect her to be a graphic designer, tattooist or piercer, but no, she's a make-up artist and also a production assistant in the porn industry.
Guess that's off the wall enough, though she's a  normal woman who gets up every day to do her job, she meets with friends, loves and lives.
Oh and as a special request of someone on the Amazon forum, who said there are never old, fat, grey-haired, stuttering guys in Thrillers, I created John. :-)

Stereotypes work if you add some sort of unexpected character trait to them. Like Gary and Sarah, but you don't need to make all characters like that. As in real life, some just fit the profile of the meek guy who has no social life, or the girl who gets drunk every weekend and sleeps around, so don't be shy and give them a well-deserved place in your book.