Started shaking in the elevator before an onsite and had to sit in my car for ten minutes first

Not nervous-excited, actually shaking, had to grip the strap of my bag on the ride up. Sat in the parking garage for ten minutes before even going in, did nothing productive, just breathed until my hands stopped. Nobody in the interview had any idea, which is almost funnier in hindsight. Started doing the same ten minutes before every onsite since, on purpose now instead of by accident, and it's the single thing that's helped most.