Richele,
I hear your frustration regarding students being late and absent. It is a disrespect of time, and quite frankly, it is annoying. About a decade ago when I began teaching, I was a stickler for timeliness and for being present to class unless extreme circumstances prevailed. I believed (and still believe) students should treat school like a job.
Over the years, I've mellowed a bit. I have come to understand that each of us has a different set of values. If one does not value his time and class, then it is up to him to obtain the information and learn the material some other way. When I feel myself becoming bothered by a student's tardiness, I say to myself, "It's on him".
Please don't get me wrong. I do sometimes have discussions with students who are repeat offenders. But for the most part, I consider that they are adults who must take responsibility for their own actions. For me, it is a less stressful way of being. I save most of my energy for the motivated students who want to learn.
Happy teaching,
Aimee