What's something that looks productive at work but actually isn't?

I'll start with a few that I see constantly:

Writing incredibly long, manifesto-like emails when a quick phone call or bulleted list would be 10x more effective.
Attending "optional" large-scale webinars/meetings and aggressively taking notes, even though the topic has nothing to do with your actual KPIs.
Over-automating simple tasks. Spending an entire afternoon trying to write an Excel macro or Zapier integration to save a task that normally takes 5 minutes a week.

What’s the best "looking busy while doing nothing" trick you've witnessed?