Acknowledge your mistakes, no matter how big or small, and apologize when it's warranted.
One time, this professor made a good-natured joke about me in front of an important person. I was rather offended, but did not say anything about it. The following Monday, my professor apologized to me in front of the entire class, though I would have been satisfied with a simple, "Sorry about that." in private. I actually had not even expected them to apologize at all. I believe it takes a certain amount of courage and humility to step up and acknowledge a mistake, however small, and say 'sorry' to one person, let alone do so in front of a room full of people who have nothing to do with the situation.
Never be afraid to show your zeal for a subject or cause you are passionate about.
I am currently taking a seminar on a very controversial author whose name many shudder to hear. Nevertheless, the professor teaching the class is absolutely enthralled with this author's work and life, and does not hesitate to make their excitement known. As a result, the students in the course look forward to class and remain engaged in the material, however squeamishly.
Always go the extra mile.
This is something I have learned from all my professors. They always do their best to make class interesting for students, as well as being extremely accessible to students outside of the classroom. It makes me feel like they really want me to learn and become better at what I do.
A little caffeine goes a long way.
"I'm not sure whether I've had too little or too much coffee," one of my professors regularly muses in class. Listening to their jittery, overly energetic lectures is fun, but it also makes me more cognizant of the negative effects of caffeine.
The fact that someone is younger, less experienced, and/or less educated than you does not mean you cannot learn something from them.
Most, if not all, of my professors never miss an opportunity to learn, even when it is from students. I have seldom encountered a faculty member at Trinity who puts down a student's comment for being 'too smart' or 'too deep.' Furthermore, they are never afraid to say, 'Oh, I did not know that,' instead of pretending that they knew something in order to protect their ego.
Be humble.
Many of my professors are extremely accomplished and, though they are proud of their work and accolades, they seldom speak to students about these accomplishments in a boastful manner. With most of my professors, I do not realize just how amazing scholars they are until I Google their names.
Don't take yourself too seriously; life is only as fun as you make it!
I take a particular course that would be the bane of my existence were it not for the professor who teaches it. They can find light in the most obscure of readings and effectively utilize self-deprecating humor to drive certain concepts into students' heads. Their lectures always remind me that life is best taken with a grain of sugar.