Some valid and sound points made on this thread.
One of the Abba guys said every good pop song should have 5 hooks.
To me the melody and lyrics should flow. Take time to even out the speed bumps. Song writing is a craft and some people have a natural talent for it.
I find I get most of my inspiration in my semi concience state when waking up. Also, picking up catchy lines from others in everyday conversation. As a previous poster said, if you just observe there are song stories all around you. All you have to do is mould them into words & music.