If it's too quick, it's probably no good
In many of my sales conversations the one thing I've learned time and time again is that if you do not take the time to walk people through the appropriate "emotional connection period" and really hash out exactly what it is they want and even get to talk about all the things they've tried that didn't work, you end up biting the bullet. These conversations seem to be the "sure things", the easiest deals in the world and wow, wasn't Bill so excited to go through with this in the first 30 seconds of the conversation?
And yet almost all of these deals fell through.
The reality is that you cannot serve someone when you don't deeply understand their needs and they don't trust you.
These types of meetings where you think they are so sold (even if they aren't) tend to drop off the radar pretty quickly and this generally leaves the sales person really confused.
I thought it was going so well, what happened?
What happened is that you didn't do your job.
You let them lead the conversation, tell you the next steps and didn't understand their emotional terrain in a way that could help you better serve them.
You pitched them as opposed to conversed with them.
You sounded like a vendor as opposed to a thought leader.
You have to be willing to take the reigns of your sales conversations and get down to their objections (why they shouldn't buy from you) if you want to see any closed sales. Otherwise, you're going to see a lot of people magically disappear when things were going "splendidly" and/or you'll hear deal breaker objections when it's all about to close (for example, the price is really $50k not $5k).
Man up. Be willing to really get to know your customers, heck get in the trenches with them and be willing to say no to premature requests for scopes of work and design work (or anything else for that matter) if you don't deeply understand their needs. In fact, make that your main goal: to deeply understand them.
That in and of itself will require you to do the necessary question work up front and is probably a good compass to see if you're headed in the right direction.