Point of Etiquette

Okay, is there a way to compliment your professors without sounding really marginal? Because I have two professors who wear just outstandingly excellent shoes, and since I'm a firm believer in positive feedback, I'd like to mention my approval. I just haven't figured out how. "Dr. L.,* can I discuss this grade with you? Also, nice shoes. Really top notch."

And since it's grad school, let's "complicate" and "trouble" the question by examining the fact that one professor is male and one is female. Does this create two protocols? How does the gender of the complimenter factor in? What if I tell you that one of the classes is pass/fail and one is not? That one of the professors is a medievalist and one a writer? That I'm really just procrastinating reading my theory right now?

^{*I don't actually call my professors "doctor." They go by first names with graduate students.}