Why is Green Day so popular?

So I turned on the radio today and I heard Green Day..  so I naturally switched to another station, and wtf, also Green Day?  I switched yet again..  no Green Day.. *phew*.  5 minutes later, they start playing Green Day again!

What's up with music these days?  Can't we go more than 5 minutes without hearing a Green Day song?

Are you sure that your radio isn't tuned into 15 years ago?

My iPod doesn't have radio, nor does it have Green Day.