There's a difference (in my opinion, anyway) between:
"I'd like to meet for coffee Wednesday. I do have to take care of (whatever). Should be free between 5-7. May I call you?"***and:
"Wednesday? Sure. I'll text you when I'm free." (Then either not following through at all, or contacting me at 9 pm.)One feels like you genuinely want to make plans, you just need a little flexibility. Like you consider spending time with me to be some sort of priority. The other feels like you want to put me on reserve, but not quite commit. Like I'm an acceptable backup plan unless something better comes along.
I have no interest in being anyone's backup plan.
This works with some people. Maybe they really like you, so they're willing to wait around. Maybe they're really lonely, and just happy to have plans.
I'm not that audience. I don't mind being alone - and I also don't have a problem finding other plans. [Case in Point: Several weeks ago, a date canceled on me last minute. I'd given up two other dates, a party, and a (free) family dinner to make those plans with him. I filled the time, but how happy do you suppose I was?]
So don't treat me like I'm so desperate for a date that I'll put up with your nonsense. I respect you enough to make a plan; show me the same respect.
Don't expect me to sit around, waiting for you to decide nothing better came along. You can't put me on reserve. I'm not a library book for crying out loud.
Listen - I'm not asking anyone to rearrange his life for me. I'm not asking anyone to move mountains to spend time together.
I'm really just asking to get the same respect I give.
***While this is acceptable, an even better plan would be to just agree to meet me at 7:30, when you know you'll be free. If you're thinking, "But what if I'm free earlier? Then I'm just wasting my time," then you're part of the problem. Dating isn't just about what's convenient for you. I expect if you really want to see me, you'll make a plan, and then kill time if needed. If the roles were reversed, that's what I'd do.