What’s good about great tracks is that they can have many incarnations. A meaningful song could have been a hit in the 50’s and then re-imagined by a fresh 80’s act.

Great songs usually make you not only want to listen but to sing out loud, dance, play along or bang the f*ck out of your imaginary drums. 

Whereas it’s working with references or writing completely original music, a commercial needs a catchy melody and a good beat.