Yes, I know, we don't take attendance. You don't earn points just for coming to lecture (except you do lose the chance to earn "clicker points". This is a small bribe at some level.)
But the main reason you want to come to class is to "get into the instructor's head". There are just too many different things going on in this class.
When I run a lecture, my goal is to provide "value added" to all of the other resources that are at your disposal for learning and understanding the materials. Lectures are especially designed to augment other resources, not supplant them. For example, I won't simply repeat derivations from the textbook. And I won't simply walk you through the online notes. Most especially, I won't use lecture to "introduce" you to new materials. Indeed, quite the contrary, my hope and expectation is that the students coming to lecture will already have looked at the assigned reading and the associated homework and will therefore already have some basic familiarity with what will be covered.
The main thing I can provide as an instructor for a lecture is to guide the students to new connections, new ways of understanding the concepts, facets that would otherwise go unnoticed or unappreciated. My goal in the lecture is to strengthen and deepen your knowledge of the materials, to provide synthesis, examples, demonstrations, and applications. I will try to emphasize those ideas that are central and fundamental to the course vs. those ideas that are peripheral or tangential. I also work hard to model the best practices for abstraction, tackling problems and showing how different topics in the class are inter-related. And finally, I can reflect on the meta-issues, the epistemology and the universal relevance of the material to the human experience. In short, my goal as a lecture is to help you move from simply seeing the material as a set of unconnected topics to seeing it as a unified and coherent branch of knowledge. This is the essence of deep learning.
Okay, if all of that high-sounding sentiment isn't persuasive to you, then here's a notion that might be compelling to even the most cynical student: coming to lecture gives you inside information on what you are going to be tested on. In lecture you learn which concepts and problems and idea are most important to me, the one person who has designed the course, the one person who is actually going to write that exam. We cover many topics in the course, and one of the most challenging aspects for students studying the exam is to prioritize so that they can focus on the most important ideas. The more time you spend with me and the material, the more likely you are to learn which topics you really need to know and which ones are less important.
One last point, if you are going to come to lecture, it's worth optimizing your time and effort. If you are browsing the web on your laptop or spend all of the lecture time working on your chemistry homework you will simply not reap the benefits. Furthermore there is a real benefit to sitting as close to the front as possible. Double-blind research confirms: you move students from the back of the classroom to the front of the class, then their grades go up. You move them from the front to the back, they do worse.
more on the value of sitting close and center in lecture, see www.altoona.psu.edu/fts/docs/SeatingPositionGrades.pdf]