Like all single men, I've committed some royal screw-ups when it comes to women. But as a male columnist*, I've also made some observations about different types of daters that deserve to be passed along. Consider this your road map for where you DON'T want to go in your love life.

Knowing how bummed I've been since my ex, Claudia, left for Europe, my buddy tried to set me up with his "fine coworker." Very kind of him, but I declined. With my heart stuck in international customs, there's no way I could make a connection. Not that I wasn't tempted. We men secretly hope we'll never have to deal with our feelings and instead can "fix" our sadness with a new woman. Problem is, we're always comparing her to the ex.

Some seemingly normal guys have a bad habit of vanishing. Excuses like "work's really busy" may be true, but there's often something else going on. My old roommate tried to woo his new girlfriend while still dating his old one. I also know someone who told a woman he was single in New York, although he was married in Ohio. Both guys checked out for days at a time.

When you're just starting to date, it's not like you're tracking a person's every movement. Still, the giveaway is erratic contact. Is he in touch every day and then suddenly MIA? Does he often cancel plans? Or does he suddenly want to meet up in an hour, after not calling all week? Beware.

With his sporty car, high-tech cell phone, and Swedish designer toothbrush, my college roommate managed to hide his insecurity behind hip stuff. He never let women get close for fear they'd find him out. So women wound up feeling rejected when HE was the one who sucked.

My advice: If his life looks like a magazine spread, steer clear. Say what you will about the guy who has a painting of poker-playing dogs or a mountain of laundry, but I promise you this: He's real.

I'm amazed at what men get away with. A partial list of nasty moves I've witnessed: checking out the waitress, fiddling with a BlackBerry during dinner, asking the cute bartender for her number when his date is in the bathroom. If a man lets the door slam shut instead of opening it for you, make that all the closure you need.

Hands on thighs, stroking things that didn't ask to be stroked, sensual innuendos when you barely know each other -- he may try to explain these things with an "Oh, I'm so attracted to you I can't help it" line. But no matter how attractive you are, he CAN help it. And if you're not getting the respect you want early on, he probably won't surprise you with it later.

Long nights and a fear of being single forever can make going back to an ex seem mighty attractive. I've been guilty of it twice, both during lonely times in the dead of winter. Recycling romance seemed far easier than the unknown, and it was... for the two months before we rediscovered exactly why we broke up in the first place. What's the lesson here? Move forward, not back. And know that it's better to be out there looking than stuck on a couch with some guy you're just going to wind up dumping anyway. He might be happy, but you deserve more.

*Jake is a real, live single guy dating in New York City.