I've been sick a lot this week. It started as a head cold, and either migrated or was was replaced by something intestinal. This has been accompanied by muscle aches (and some weird muscle cramps), lethargy, and a nearly terminal inability to concentrate.
All this led me to observe that what I'd really like to do is pull one of Anne Rice's vampire tricks: just go into the earth for, say, a year and a half, and then come back up when I'm healed and everything is working right.
...Which led immediately to the realization that if I did that, Firstborn would have jumped from four-and-a-half to six years old in my absence. LG would have gone from still learning to walk to speaking real English words. Also, my wife would kill me, but that's quite a lot less startling.
Having kids has made me acutely aware of the passage of time.