Green Day song meaning
"Green day" is a slang saying for a day spent doing nothing but smoking weed.
Obviously, this song has a lot to do with getting high and the feelings that one experiences from marijuana intoxication. But aside from that, the song also has a few lines about a relationship that is not working out the way the narrator would want it to. Having a green day allows him to think everything over, but all he finds is helplessness and regrets. Yet, he expresses that the relaxation and absent-mindedness of being "stoned" gives him a fresh experience and makes him feel like he has "found something new".