So what might they be thinking when they see your space?
You'd rather be fishing (or skiing, or skydiving, or building birdhouses). Evidence: Pictures and artifacts from your hobby on every surface.
There's a delicate balance between sharing your interests and giving the impression that you're daydreaming all day about jumping out of planes or skiing, according to Barbara Pachter, business etiquette expert and the author of "New Rules at Work": "Pictures of your hobby are good conversation starters, but if you have too many of them, it makes people wonder whether you're really daydreaming about fly-fishing."
They can hang around. Evidence: A full candy dish, aspirin in the drawer, well-tended plants, pictures of children and babies.
"Things like an open door, candy, a comfortable guest chair, and photos of people--but not pictures of objects--signal an extroverted workspace that people will feel free to linger in," says Sam Gosling, a professor of psychology at the University of Texas.
They shouldn't hang around. Evidence: Flimsy guest chair, guest chair covered in files, or no guest chair. Your desk faces away from guests. Minimal or no decoration.
"Even if your office has photos or artwork, but they're images of things and not people, [people] can make an assumption you're more introverted and might not want them to linger," Gosling says.
You demand respect. Evidence: Multiple degrees on the wall, awards on the shelf, pictures of you and important people, magazines featuring articles about you. The plaque on your desk says your full name and title, and lists your advanced degrees.
"Name plaques form a strong impression. If it says just your first name, people assume you're friendly and approachable. If it has a formal title, they think you want to be respected for your rank," Luccioni says.
You've just been hired, you've just been fired, or you'd like to leave soon. Or you'd rather be temping. Evidence: Files in boxes, no decorations, no books, no plants, no pictures, and no name plaque.
They should avoid doing business with you. Evidence: Messy piles of papers on every surface. Half-eaten donuts atop teetering stacks of binders. Carpet stains.
Experts agree that a messy office can seriously damage your reputation as a conscientious person. "It's hard to function in a messy office, and people assume your office chaos will spill over to their project and their files will be lost in your mess," Pachter says.
Gosling pointed to research that shows people read much more than they should into a messy office. "People think that someone with a messy office is less agreeable, which may not be accurate. My guess is, people assume a mess is inconsiderate."
You don't take the whole "work thing" too seriously. Evidence: Humorous posters, ironic bumper stickers, whimsical images, and toys.
Experts have several suggestions on making sure your workspace matches the image you want to project.
Err on the conservative side. Especially if clients visit you or if you're in a high-traffic area, you want to make sure people don't stop in their tracks to gawk at your collection of teddy bears or tiki torches.
Be careful with controversial items. "Consider the cost:reward ratio of putting up something like a political campaign poster," Luccioni says. "You might find kindred spirits, or you might offend people and get a first meeting off to a bad start." All experts say anything potentially racist, sexist, or homophobic, or otherwise disparaging of a group, is a no-no.
Check your employee handbook, or ask HR. Your company probably has some guidelines on decorating your work space. They might not even permit any decoration, which makes the issue moot.
Follow industry norms. Some industries demand a strict image of seriousness, while others are more laid-back. A poster with a funny or counterculture slogan would be more appropriate in the office of an advertising copywriter than the office a defense attorney.
Consider the physical arrangement. "A desk can act as a barrier and give formality, which is good for reviews but can be intimidating," Luccioni says. She adds that a small circular table allows everyone to meet on an equal basis. A power difference, if you want that, can be achieved by giving guests smaller, flimsier chairs.
And if you tend to make snap judgments about others' offices, try to look at the bigger picture, Gosling recommends.
"Any one item can have many different purposes. If someone has a plant, maybe they have a green thumb, maybe they're into feng shui, or maybe the plant was left over from the last person in that office. If you see someone with a super neat desk, how do you know whether they're truly neat, or whether they swept everything into a drawer before you stopped by?"