hahaha... duno... maybe cos ladies always more free and waiting for the sms to be as a form of assurance bah..
for my bf, if he doesnt reply,
1. he has no answer in mind
2. he is still pondering about the stuffs mentioned and discussed
3. he is busy
4. he is afraid of negative response from me
5. he doesnt wana promise me anything
so i guess, its either he got offended by my reply, or he is busy lor..