Dealing with men is not easy. It's easier if you have a partner, and you're no longer looking for romance, but it's still not easy. By and large, guys are ill-controlled masses of hormones, and it makes us behave in ways that are often unpredictable and annoying. (Paradoxically, this is a large part of what makes them so fun. Their naughty bits help a lot, too.) Maybe I shouldn't generalize. Maybe you're the guy who never lets his cockhead do the thinking. But probably not. I think I'm among the most stable and settled and drama-free guys I know, but even I have been known to treat someone badly in my quest to get laid.
Anyway. My point here is not to bemoan the state of men: it is what it is. My point (which you would certainly be forgiven for not having gotten since I haven't made it yet) is that there are ways to deal with guys that can minimize their ability to drive you crazy (in a bad way, that is).
You need a set of rules. If you don't like rules, you can call them principles, but then you're less likely to follow them. Sometimes I don't follow my principles/rules, and then I almost always regret it and end up telling myself, "You knew that was a bad idea, but you did it anyway. Now you must be punished! No, wait, punish someone else instead: it'll be more fun for you and a good lesson to the other guy that life isn't always fair." Or words to that effect.
The rules are ever a work in process, and you need to strike a balance between too much and not enough. You don't want to be that guy who carries a list with him and, after sharing half a drink with another guy, pulls out the list and says, "Sorry. I'm enjoying this conversation, but you violate number 27, and there's a good chance that if we kept this conversation up, I'd conclude that you also violate numbers 362 and 365. I think it's best that we both move on before either of us gets any more hurt than he already is." And, really, I'm not talking about criteria for who you'll marry here. If you're only attracted to left-handed redheads who played third base in little league, I really don't want to know about it. I'm talking about rules that might be ever so slightly more universally applicable.
Anyway. A few of my rules:
1. If a guy jerks you around before he's even met you, he doesn't get to meet you. I understand that there may be perfectly valid reasons to cancel a date, but nine times out of ten (and I'm being generous here), if you're supposed to meet a guy on Friday or Saturday night, and he backs out at the last minute, then you were only his backup plan. When a lot of men make plans, they silently append to every statement "unless something better comes up." You don't want to date a guy like that. You don't even want to hook up with a guy like that. Unless, of course, he's hot and you happen to find yourself in the same location as him and that location is conducive to hooking up. But that last exception pretty much only applies to bathhouses and glory holes. This rule extends as far as the third date (or hookup or whatever). If you've gone out with a guy three times, and he has to back out of the fourth or subsequent date, then he's earned the benefit of the doubt. Unless he's given you an excuse that's transparently false. You don't need to date anyone that dumb, but you can still fuck him.
2. You can't date a man who's taken. If a man has a wife, a girlfriend, a partner, a boyfriend, or an unhealthy relationship with his household pet(s), then he's not available, and you're not dating. At best you're having a drink together prior to fucking like bunnies. There's absolutely nothing wrong with fucking like bunnies, with or without the drinking, but be clear that's what you're doing. Don't waste your emotional capital hoping for a relationship with a guy who can't have a relationship with you and who wouldn't be a good bet for a relationship if he ever became available.
3. The merest hint of unsafe sex should send you packing. If you're online with a guy, and he asks whether you ever fuck bareback, end the conversation. If you're getting hot and heavy with a guy and he takes your cock out of his mouth to ask whether you want to fuck him bareback, put your clothes on and leave. It doesn't matter how it's phrased. The statement "I always use a condom, but I'd let you fuck me bare" is always a lie. Or at least the first half of it is.
4. If a guy isn't interested enough to return the second call or e-mail, he's not worth bothering about. Don't make a third consecutive contact. It just makes you look needy, and neediness is never attractive. Some people would tell you not to make the second consecutive contact, but I think that's unreasonable. I know there have been times when I've gotten a voicemail or e-mail and haven't been able to respond immediately and then, well, kind of forgot. In some of those cases, a second phone call or e-mail has been extremely welcome. (I always apologize for having been thoughtless in such situations; the guy who didn't get back to you until the second contact should also be apologizing.) So if you want to make a second contact, go ahead: the rules say it's okay! That's what they're there for, so you can rely on them rather than obsessing about whether you should go ahead and send the forty-first e-mail in case the first forty got blocked by his spam filter.
5. Don't date a guy who only ever calls you to do things at the last minute. If a guy suddenly got tickets to the Mets game (It should go without saying that you don't date a Yankees fan: you may, however, fuck them. Without lube.), it's cool and thoughtful for him to call you and ask you if you want to go. If he's always calling you at the last minute for dinner and a lay, then he's probably using you as his back-up date. The last minute call is always, however, appropriate behavior for a fuckbuddy, and neither of you is allowed to be upset if the other isn't available.
I think that's most of them. Some of them obviously don't apply to me any more since I am no longer dating. And they're all subject to modification (most notably, there's a statute of limitations: people and their circumstances change, and a guy who was a jerk in 2003 might be better now) and occasional exceptions, though as I said before, I break them at my peril. They're good rules, and they're there to make my life easier and especially to make it stop thinking about a guy who isn't worth my time. I reckon your rules (which you probably have even if you've never articulated them) are different, but mine work pretty well for me.