Think about it this way. Have you ever exchanged numbers with someone you sort of tolerate but don't really like, from work/college? It's happened to me. Not just females but "friends". They tell me we should hang out, etc or invite me to something.
Now, with such a person whose company you're not really keen on, you still have a tendency to try and let them down gently with excuses or not answer the calls/not call back. You can always blame it on being busy after.
Now contrast that thought with someone you really like. If you have a decent interest level, do you act that way towards them? I personally don't. If a good friend or a chick I like call me, I may not call back on that day, but I make a mental note and make sure I call them back, because subconsciously I know they have something to offer to me that I don't want to miss.
Now, with such a person whose company you're not really keen on, you still have a tendency to try and let them down gently with excuses or not answer the calls/not call back. You can always blame it on being busy after.
Now contrast that thought with someone you really like. If you have a decent interest level, do you act that way towards them? I personally don't. If a good friend or a chick I like call me, I may not call back on that day, but I make a mental note and make sure I call them back, because subconsciously I know they have something to offer to me that I don't want to miss.