If you have a 3.75+ GPA, high GRE/MCAT/LSAT scores, extra cirrics, coveted internships, astounding personal essays, etc., you are a very strong candidate. The problem is that there are thousands and thousands of strong candidates.
It’s a lot like being very attractive and wanting to be a model, or being a very good singer and wanting to make a career of it. It’s highly competitive and a lot of talented people are going to be rejected, so keep your expectations realistic.