They will exclusively use a Mac. It doesn’t work any better, but it’s shiny.
They will spend 90% of their day wearing headphones. They’re not even listening to anything. They just don’t want you to talk to them.
They’ll frequently order half caf non-fat extra dry four shot lattes. They taste awful, but it’s fun to say.
Their eyes will twitch at the sight of bad kerning (that’s the spacing between letters, for us mere mortals).
They will send you pointless texts at 3am with no explanation for why on earth they’re awake at that time.
Photoshop crashing could likely send them on a murderous rampage.
Their desks are a hodgepodge of inexplicable tools: a single post-it note reminding them to buy more post-it notes; six empty cans of energy drink; a cactus that might be artificial, but they water it anyway; a rock, because of reasons.
They will interrupt you mid-conversation to point out the lovely aesthetic appeal of that cloud there.
They may ask to leave a restaurant if the menu’s layout is particularly irksome.
They read comics you’ve never heard of, watch shows you didn’t know had started yet, and nod along to anything from classical rock to a radio ad jingle.
They’ll whip out their camera to take a photo of an apple core in the gutter then show you their Photoshop result a few hours later and you won’t understand how but it will be hauntingly beautiful and it will piss you off.
They despise Comic Sans with a burning passion.
They will occasionally lean back from their computers, pause, then release a guttural shriek akin to that of a walrus being threatened with a golf club. You’ll be too afraid to ask what’s up.
There is a very real risk that they will be unable to pay for food because they spent their grocery money buying pretty new fonts.
(Just joking, of course. Designers are actually wonderful and unique people, exempt from the constraints of such ridiculous stereotypes and who surely aren’t at all bothered by the rendering of any font by Chrome.)