If I had special powers, I assure you that my very first exercise of them would be to arrive to class on time, every single day. Alas, I have none.
It pains me nearly as much as it must pain you when I lumber in late with my laptop. Is it not richly ironic that I myself taught for two years, and nothing (to exaggerate slightly) galled me so much as my students' tardiness?
(Even if my only special power were that of invisibility, and I could thereby sidestep the drama of a conspicuous late entrance, I realize that you might still find it unsettling if I simply showed up in my seat five minutes into class.)
So it goes without saying that I sympathize deeply with your vexation--I share it, in fact. If I had any power at all to alleviate it, please believe me when I say that I would not fail to do so.