1.
Their absent-minded pen-fidgeting during meetings is at a dramatically heightened level from everyone else.
2.
The. Constant. Tapping. (Even if it is surprisingly rhythmic.)
3.
They have an uncanny ability to stretch their fingers into what look like complicated Harry Potter spells.
4.
They practice chord progressions during boring meetings.
5.
They sing the harmony part instead of the melody during karaoke.
6.
And they sing the instrumental solo parts, too.
7.
Dynamic nervous knee‐shaking.
8.
Their fingernails are ... different from other people's.
9.
Their hand-clapping technique is worryingly impressive.
10.
They're very particular about their headphones.
11.
And as soon as your back is turned, they're playing air guitar.
