Android doesn't show music for 2 days

I didn't manage to grab a picture but I added music to my Android through the USB connection. Android is supposed to find your music automatically. It didn't. I tried killing the music app and relaunching and seeing if that fixed it. No.To play the music I had to resort to ES File Explorer which was really annoying because it's music player is modal. Meaning if you try to do anything else the music stops. A couple of days later the music finally showed up in the built in player. WTF!