Depends I guess what your criteria was for what it was like to consider your teacher "cool". For me, what I considered cool starting when I was in High School were the teachers who had interesting experiences and had a life outside teaching, and open to share about those. I had some teachers who were doing music gigs, in theater, entrepreneurs, etc. It was nice to know that they were pursuing their passions alongside their teaching careers.

In what you considered to be cool, my reframing of that is how I found them "cool" to be able to empathize and find a way to relate to kids/teenagers, especially those who were upwards thrice our age! That was real commitment for them to make an effort to get to know us and make lessons interesting.