Starting with iTunes 12.2.2, you can tell Apple Music that you don’t like a For You recommendation. Previously, you could do this on iOS devices, but not in the iTunes app on the desktop. To tell Apple that a For You recommendation is not really for you, click the … button next to any song, album, or playlist, and choose Recommend Less Like This.
Apple Music will take your dis-recommendation into account when it recommends music in For You. It’s a good idea to do this whenever you see something you really don’t like, just as it’s important to click the heart (♥) button to tell Apple Music what you do like. Over time, you’ll get better recommendations.