What's the strangest thing you've ever forgotten?

I was reading this question and it instantly brought back the sicky-feeling I’ve felt so many times after suddenly realizing there’s something I have forgotten… sometimes for a long time, or with catastrophic effects.

Some of my highlights:

I highschool I once forgot I had a class. For a month. I was sitting in the cafeteria with my binder open and a friend glanced with a puzzled expression at the inside of it where I had my schedule pasted, asking, “Why are you always here during this period? Don’t you have a compsci class now?” And suddenly, with that sick feeling in the pit of stomach, I realized I did—and that I’d been skipping it for a solid month.

When I was young, I was forever forgetting my dog tied up to places and things. I’d be at home, hours later, call out for the dog, and be puzzled when she didn’t come running. Scratching me head, I’d be searching around and trying to remember the last time I’d seen her and suddenly all the blood would rush into my face as I’d realize I left her tied to a pole outside the convenience store… three or four hours earlier.

I once forgot I had a job. Just started sleeping in late, saving my pennies, falling back into old habits as I assumed I was unemployed. When a welfare cheque didn’t arrive at the end of the month, I called my worker, who was baffled to hear from me since I hadn’t been on welfare in more than a year. I suddenly realized, with a sick feeling, that I’d simply stopped showing up at work without notice.

I regularly forget what season it is. I’ll be glance out the window, see a layer of white on the ground, and suddenly feel vertigo and panic as I realize I was expecting to see green grass and have no idea what month or year it is.

A couple of months ago I had a nightmare where I dreamed I was nearly 50. I was near tears, approaching people in my dream and trying to explain to them that I can’t be 50, that 50 is old and I’m not old. I woke up panting and sweating, relieved that it was only a terrible, terrible nightmare… until, with a jerk of terror that made my heart start pounding, I realized that I am almost 50.

How about you? What’s the strangest thing you’ve ever forgotten?