Had a coworker once whose calendar always looked so busy. It was hard scheduling anything with him. Funny thing, we were basically a two-man team working on the same stuff. How was he so busy all the time when I didn’t have comparable busy slots? And then one day I happened to get a look at the titles of all the stuff on his calendar. He just put his own reminders on his calendar in the default 30 minute blocks. He wasn’t busy at all, just filling up his calendar with useless shit and making things difficult for me.

I let him burn a few times for it when I could’ve intervened.

Edit: Thought I’d add the guy was a piece of work for other reasons, as well. And, the lesson he taught me - don’t let full calendars make you think someone’s really busy and productive. Judge that from how much shit they get done.