If it alters your mood in a way you don't like, you already know the answer. You just have to decide if you want to act on it.
I mainly listen to relaxed slow phased rap music (Finnish) and really heavy metal music like meshuggah and many more. I'm mainly concerned how much I agree with many of the lyrics of the rap music I listen to. Buuut i'm starting to think I just happen to agree with them.
My favorite finnish metal band that sings in english is Ghost Brigade. If your interested.
I agree about moods, I tend to listen to certain music depending on my mood but opinions... I don't think so.
Let it change you, that is what art is all about.
Nah, whatever happens, happens.
It's not the music altering you. Why do you think we have so many silly metal bands in Finland? Everything happens for a reason and although I usually prefer the covers made by Eläkeläiset over the original versions, I still find myself pretty much in the same tight spot. Just... Don't think too much about it. Breathe.
Music is good for the soul. It can send a message to someone, or tell a great story. I love music.