A state of mind in an office/work environment where a person guards their pens as if they were gold. The pen crazy person often snaps or gets the shakes if someone uses one of their pens with or without permission.
Pam: Anyone got a pen I can borrow?
Cindy: Here's one. Keep it.
Pam: Are you nuts?!?! That's Kelli's pen! If she knew I took her pen, she'd kill me! She's pen crazy!
When you set your alarm clock for a certain time and then suddenly wake up and jump up thinking you overslept. You then look at your alarm clock and notice you didn't oversleep, you actually woke up way earlier than you had planned.
I set my alarm clock for 8:00 AM because I was supposed to pick up Kelli at 9:00 AM. I jumped up thinking I overslept and looked at my alarm clock. It was only 5:23 AM. I underslept.