I'm a professor, and I'm afraid I was once a typical student. I went a little wild my freshman and sophomore years, then settled down somewhat, but not completely. I blew off almost an entire quarter of calculus to go to the beach. I decided not to write the three assigned papers in one of my classes because I judged them not to be worth the effort. I was a party girl. I often went to class with a hangover, or not at all. I sometimes fell alseep in class, and spoke up in class maybe twice in 4 years. After a few years, I became interested in a subject and started caring more. I managed to get involved in research with a few faculty members, improve my GPA, and score well enough on the GRE to get into a good graduate program.
I also took responsibility for all of this behavior. What I didn't do was blame my professors for my bad grades. If I skipped class, I did not go to the professor and ask for a personal make-up lecture on the material I missed. I did not make up stories or excuses about why I missed an assignment. I did not ask for extra time on assignments, or ask to reschedule a test so that I could go on vacation early. I didn't beg for points on exams, or for a grade higher than the one I earned. I felt that it would have been deeply shameful to do any of these things. I felt that it would have demonstrated a lack of respect for my professors, and it would have been dishonest.
What pisses me off about some of my current students is not that they sometimes screw up (I can relate to that), it's that they expect me to spend time that I can't really spare (and don't want to) helping them clean up their messes. They refuse to accept the consequences of their behavior. They are shameless and disrespectful. I'm grateful that most of my students aren't like this, but I resent having to spend precious time with the bad ones that I could be spending with the good ones.