A lot of celebrities have recently been putting on friendly faces when their exes come around (Kendra Wilkinson and Hugh Hefner, Madonna and Guy Ritchie, Mandy Moore and DJ AM, and Nick Lachey and Vanessa Minnillo, to name just a few). And many of us non-celebrities have, at one point or another, dumped someone with the parting words: "We can still be friends." But let's be realistic for a moment, shall we? There's no such thing as being "just friends" with an ex. Here's why.














