Let's be honest here for a minute. High school teachers are amazing. They deal with teenagers and their attitudes and hormones and such, but most teachers don't have the ability to teach what they want. Usually, they are forced to teach to a test, which is unfortunate for both the teacher and the student. High school teachers are often not allowed to teach things that are really fun about their own subject, and therefore, it's hard to keep students' attention. College professors have a lot more freedom to teach what they like, not to mention students are more likely to be interested in the course since they signed up for it, which is a luxury most high school students don't have.

High School Teachers: Can talk to students during or after class is finished.
College Professors: Have mandatory office hours.
High school teachers are often on a tight schedule with a full day of back to back classes, therefore they don't have time to make appointments with students to talk about problems or questions. Professors don't usually have back-to-back classes so they have the time to have office hours and encourage students to stop in and talk to them about what is going on. A lot of times, professors keep track of the grades that students are getting so they know what to talk to each student about.

HST: Take roll call to make sure you attend class.
CP: Don't necessarily take roll, but know when you are absent.
It may sound weird that college professors "know" when you are absent, but it's scarily true. I had a professor pass me in a hallway one time and said that he noticed me walking in late his last class. It freaked me out because I was in an 80-person class. College professors definitely know when you are not there. Most colleges have an allotted number of absences that a student is allowed until they get in trouble so I would advise against skipping all the time. Professors may have a huge class but they definitely don't miss a thing!

HST: Let you know all of the work you missed when you were absent.
CP: Expect you to get notes from another student.
High school teachers typically let you know everything you missed, give you the assigned readings, give you a copy of their own notes and sometimes even show you the slides they went over. Professors expect you to look at the syllabus and look online to see what readings you may have missed as well as get the detailed notes from another student. Getting notes from another student can be especially daunting if you're shy and have no friends in that class. Trust me, it's almost better to just go to class.

HST: Write notes that you must know on the board for you to copy
CP: Lecture nonstop and let you figure out the most important points
This is also very daunting. High school teachers seem to write all of the important things down on the board or in their notes for you to see. Professors, especially in lectures, usually lecture according to a bullet point list. This leaves you trying to write down the most important details of what they are saying. Most of the time, professors will let you know what the most important thing they are saying is and what is just a fun fact, but there are other times where they will let you take your own notes.

HST: Expect you to get your homework done.
CP: Expect you to have a working knowledge of the subject matter.
In high school, teachers (for the most part) need you to finish the homework in order to know the material that will be on the test. Professors really hope that you will leave their class with a full understanding of the material. They don't want you to just throw the information back at them, they want you to be able to be analytical and thoughtful as to how the topics relate to the world as well as your major.

No matter the differences, teachers and professors really care about their students and love their job. These people have a lot to do in their jobs and no matter the differences they really have a great time teaching. Those teachers and professors that truly care, you can really see and tell how much they love their jobs. Whether you are a high school teacher or a college professor, I respect you and how you have devoted your lives to helping young people learn.