Too many meta tags a bad thing?

I control a website where I have placed 20 or so meta tags. People have told me that too many meta tags could lead to people reaching your site for an unintended purpose. Others say that more is better because you can get your site to the top of search engines. I've done my research and come to no real consensus.

I'm still confused about this concept and I'm unsure what to do with my website now. Also, do meta tags affect your search engine ranking? (e.g. Too many meta tags makes your site less "valuable")