I usually say something generic that makes it clear the “issue” is mine like “this isn’t my vibe” or “I’m not feeling this today” or like, “I’m not sure this is my thing” just super generic, no strong conviction and an I statement. But the important part is to suggest something else, otherwise I’m just offloading my problem, it’s no one’s problem but mine if I don’t want to listen to classic rock for example so if I just tell you “I have a problem” that implies I’m expecting you to fix it. If I give you a problem, like I don’t want to listen to this, I also need to provide my own solution. “This music is just not hitting for me today, could we try some alt rock instead?” and if they agree I provide the music. I’ve never had an issue with this method and I also hate when people offload their problems onto me without providing solutions so I try to treat others how I want to be treated and cover both parts, politely stating the problem and offering a solution.