Decision Time

So, I've long thought that there was something weird about the dating game - well many things maybe. But, lately I've been thinking about this weird phenomenon that happens to me sometimes, and to many others that I know. There's this guy/girl that is mildly interested in a girl/guy so they take them on a date. The date is fun - they have a great time so they decide to do it again. Second date - much the same - fun time. Well this whole time the guy/girl is thinking to themselves: "I wonder if they are interested as well...I'm having a good time with them...hmm...maybe this could work out..." So they go out with the significant girl/guy again. Once again they have a good time. Then they get the post-date text..."Hey thanks for taking me out, I had such a good time! :)" The next day they get another text: "Hey, what are you up to today? Hope everything is going well! :)" That's it - game over. The blatant use of exclamation points and smiley faces gave it all away - your cover is blown. Now the guy/girl knows that the other is interested. At first they jsut suspect - they aren't sure, and they let their inner-selves talk them out of it. But, subsequent texts follow - each interlaced with more and more punctuation and smiling faces. Until the day comes - theres no room for doubt any longer. They know the other is interested.
They should be way happy right? The two of them should hook up now, and be happy, right? But, it doesn't happen that way. All of a sudden our initial guy/girl who asked the other out isn't that interested anymore. For awhile they respond to the texts with gusto, then slowly responding becomes more of a chore, until they don't respond at all. Initially they may take the other person out, but as the dates winds on they realize that they aren't nearly as interested as they thought they were before they realized the other was reciprocating feelings of interest.
Why?
Why does this happen?
Well, I don't really know - but I am prepared to propose an answer. When everything is vague and unclear it's easy to still be interested. Theres no commitment, no decisions, just interest and those exciting tinglies inside. But, the second the other party shows their interest all of a sudden it's D-day. Now you've got to decide - no more playing around. If you take her out again but you aren't really interested then you're leading her on - if you don't take her out again then you are breaking her heart because she is interested now. What do you do? Well you get all frustrated with the whole thing, and with yourself because you realize that you weren't really that interested in her in the first place. But, it took her forcing you into decision time for you to realize it. Interesting...isn't it?