Rejection is a fine art that requires tact, sensitivity, and thought...if you're going to do it in a humane way. There are two types of rejections:
Rejecting the Jerk: In this instance you're allowed to be as creatively mean as you want because he deserves it if he's been badgering you and creeping you out.
Rejecting the Nice Guy/Friend: This is a tough one because you have to get the point across while limiting the pain for him.
So, how do you go about rejecting the guy you're friends with when he tries to take it to another level? It's a delicate balance of firm and gentle. Firm, because he has to get the point so he doesn't keep trying. Gentle, because he doesn't deserve to be hurt just for finding you attractive enough to ask on a date.
Apparently, not many women know how to accomplish that balance. Or, they just don't care. I have a few mean rejections in my past:
The "I Don't Respect You Enough to Answer"
A friend recently did this to me and I'm still annoyed about it. Remember my "phantom date" situation where the girl and I kept saying we should get together, but it wasn't happening? I decided to get off Facebook messaging and "take the bull by the horns" by texting this girl and suggesting a weekend for us to get together.
So a few weeks back on a Thursday, I texted her saying I had time the upcoming weekend to get together if she wanted to. And...no answer.
This girl was my friend, so I was doubly annoyed. Basically, she didn't have enough respect for me to say "no." So she ignored me. By texting on a Thursday, I gave her an easy "I'm busy" out she definitely could have had plans for the weekend by then.
Her tactic was effective; I won't try anymore, obviously, and I don't find her attractive anymore because of her behavior. To make matters worse, I have our conversations about getting together in Facebook messaging, so she was encouraging me to try to get together with her. But it may have damaged our friendship because it's not cool to ignore someone, unless they've been a total jerk to you.
If a guy is nice enough to ask to spend time with you, the least you can do is answer, even if you don't want to do it. Just say you're busy, or say "no." Treat him the way you'd like to be treated.
Bad rejections like this are discouraging for the person getting rejected. When people ask me why I don't try harder, I point to things like this and say, "See what happens when I try?"
The Unfulfilled Lie
I asked a girl who runs in the same social circle to get together for dinner before a mutual friend's party. She told me that she couldn't go out that night because she had stuff to take care of. Fair enough.
But what happened? She showed up at the party. I was torn between anger and admiration/respect for the sheer audacity of her move. We chatted that night as if nothing weird was going on. Needless to say, I didn't try to ask her out anymore.
The most respectful way to reject a friend is to keep it vague. A simple "I'm busy" will do the trick. Remember, if someone is into you, they will hang on your every word. So if you say something like "I'd love to, but I'm busy," they will see hope in the "I'd love to." Just stick to "I'm busy" until they get the point that you're not interested in romantic dating. A normal person will probably give up after being told twice.
Keeping it vague allows you to avoid getting caught in a lie. One of my old standbys: "Oh, I can't go because I have to pick up my parents from the airport" sounds nice and foolproof, but you'd be surprised how easily lies are proven false. Just don't leave yourself open to getting caught.
One other thing. I'd steer clear of saying stuff like "Well, I feel more comfortable as friends." It immediately makes things awkward. And they can always come back with: "I didn't mean it in a romantic way," and then you both feel dumb.