You hear that, nice-guys? You're not actually nice. You're just nice so you can cling on to a woman and relationship, and suck them dry until nothing is left but boredom. You're clingy, and the only reason you're nice is to please others, you subservient little worm.
So REMEMBER all you have to do is ACT LIKE YOURSELF! So if you're naturally a nice person then...wait...you have the...but then....the peanut butter...how come...TRICK QUESTION! Nobody is really naturally nice! Just act cool, somewhat distant, and sometimes be sort of nice, but layer on some distant-ness on top of it for that "he's not too nice" effect.
Seriously though, if you're taking advice from a site called "heartless-bitches.com" then I think there's a problem. Of course there are people who are going to be too clingy, but labeling all nice guys that way seems like a stupid way to box a segment of people in that the writer has had trouble with in the past through this piece of writing.