Yes, this has really fucked me up with emails, phone calls, and letters more so than anything like LW comments. Luckily, I've largely overcome it nowadays through conscious TDT-style reasoning.
It's pretty reassuring to know that other people suffer from the same ridiculously dumb problem.
My problem is that I need to train myself such that whenever a case like that happens, I actually consider the problem in an appropriately rational state of mind and apply TDT-style reasoning. Otherwise, I just make fake commitments that don't register and never get executed.
This sounds like something important to train for in general though.
I often feel guilty for ignoring other people's comments or questions, and frustrated when other people seem to be ignoring me. If I can't indicate to someone exactly why I'm not answering, or can't receive such an indication myself, I can at least help my future selves and others obtain a better probability distribution over such reasons. To that end, I'm listing all of the reasons I can think of for someone to not respond to a comment/question, to save the effort of regenerating these hypotheses from scratch each time and prevent the possibility of failing to consider the actual reason. Note that these are not meant to be mutually exclusive.
If I missed any reasons (that happen often enough to be worth including in this list), please give them in the comments. See also this related comment.