iMessage confusion

Hi! I just have a few issues about iMessage that annoys me and I am not sure if there is a solution for this. my iMessage works perfectly fine IF the receiving person is connected to data / wifi. But assuming the receiver is not connected to internet / wifi, My mesages still send as "Blue Bubbles". it is sent but not delivered, awaiting for the receiver to connect to a data/wifi. Not assuming it is an emergency message and after sending it on iMessage, I tap on the message and send it as a "Text Message" instead. Now that I have delivered my purpose which is to give a message, later on when the receiver connects to a wifi/data, he suddenly receives the delayed iMessage.

What annoys me is that i have to send double messages ( iMessage then Text message ). Then the receiver would freak out later on because of the delayed iMessage he or she receives. I don't want to turn my iMessage off since i have friends who chat me on their iPads / Macs

I Hope someone can clear to me if this is indeed a feature or not