Last week a coworker sent a group email about a computer glitch some people were seeing and how to fix it. Yesterday he mentioned it to the group again.
Today a different coworker asked me for help because they were having that problem. They said they didn't pay attention before because they weren't having the problem then.
It really annoys me, first because understanding the glitch was an opportunity to learn something even if it never affected them, and second because they wasted my time because of their apathy. It feels selfish. "This doesn't affect me so I don't care, and if I need to care later I'll just ask."