You can draw inspiration from anything. If you’re a good storyteller, you can take a dirty look somebody gives you, or if a guy you used to have flirtations with starts dating a new girl, or somebody you’re casually talking to says something that makes you so mad - you can create an entire scenario around that.
"I got my first guitar when I was twelve. The day I learned to play was the day I wrote my first song. And I never stopped. I would get home from school and play until my fingers bled." -Taylor Swift