How about because you think you look wrong when you're late? Or it makes you stand out if you walk in late, or people might not think you have it all together, they might judge you? I've been like that in the past in fact, I would be near panic attack if I was going to be late, I've worked on that issue a lot, do my best and let it go. The world will not come to an end if I'm late-this is why my current thread is titled "Living in the Gray." Accept the fact that neither you, nor anyone else, is perfect.
It seems you probably do have some boundary issues with your W. Write those out and discuss with your IC but be clear within yourself as to what your boundaries are.
You're allowing your resentment about it to grow and affect inconsequential interactions, so figure that out.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss