I only have so much mental awareness to deal with things in the world and I tend to choose to put them into paying attention to my girlfriend, working, playing with computer/home automation stuff, and politics, as a result I tend to miss things that involve opening the mail.
I've even thought of using the home automation hobby to help make up for my pathetic abilities at remembering stuff. I've thought it'd be really neat if my computer could tell me what I'm supposed to be doing in the next couple of days when I get up in the morning...
Although I can get all of the automation stuff working, there's still a weak link--me. This is only as good as the data entry. (Though having it tell me what I'm doing is still a step up from a day planner, as those you also have to remember to look at after you entered the data.
Also I somehow accidentally managed to get ALSA to read the SPDIF input from my gaming computer and mix it with my music server, which finally lets me cross something off of my long term todo list.