I feel like cover letters are an easy way to show that you've thought about the company you're applying for, but in my experience I've never got the impression

I feel like cover letters are an easy way to show that you've thought about the company you're applying for, but in my experience I've never got the impression that my cover letter was actually read in the application process. I could be plenty wrong though, and I'd love to hear from HR/recruiters about their experiences with cover letters.