I hate tipping. I do it, but (A) I usually don't carry cash on me (who does these days?), and (B) I don't understand the logic behind who should be tipped and who shouldn't. Why do we tip waiters but not flight attendants?
But most importantly, why don't students tip professors? In this economic downturn, every cent matters. If we do an ok job, we should get 10% of the tuition for that lecture. For an excellent job, we should get 20%. Given that students pay ~$100/lecture, and that my class has 200 students, I'd be getting $2,000 every time I give a mediocre lecture and $4,000 every time I give a good one. This will surely increase the quality of education.
Alternatively, I guess I could start singing about God and send the TAs with baskets around the class to collect money.