I'd like to think that I coined this term, "Tie Anxiety". It occurs in an office environment where people who normally don't wear ties are seen wearing ties. How common is this and what is the reasoning behind it? I've often heard "dress for the job you want, not the job you have" - I'm trying to reconcile the double standard that I've witnessed on several occasions. I've also heard "How'd the interview go?" several times.
I would say that there could be several reasons for the "tie anxiety" but I will share with you the three most common that I have seen:
"Tie guy #1" - It isn't the fact that he is wearing a tie. It is the fact that in a laid back office with a lacks dress code that he comes in with his tie on and assumes that people should treat him different. Whether he be treated like a boss, a superior, a person with more knowledge, or whatever. "Tie guy #1" isn't trying to impress, he is impressed with himself. He will put off many people in the office but his act may work on a few people and if it works on those making decisions... well all of a sudden tie guy #1 can keep wearing his tie and his schtick. The anxiety is that we have to deal with the pompous guy who thinks we should treat him different because he has a tie on.
"Tie guy #2" - This is a well meaning guy who breaks out the tie because he wants to impress or make a good impression with the higher ups. He could be a brown noser or just a good guy. But this guy comes to the office with just his tie and means no harm. The anxiety here is juvenile. It is because co-workers may think that now they might appear sloppy or unprofessional and worst case scenario... the tie may become part of dress code.
"Tie guy #3" - This guy comes in to work in his suit and tie because he is interviewing with other companies before, during, or after work. People surely understand that this may be going on. The anxiety is that your company may be losing a good worker, that tie guy #3 might understand a reason to leave that you don't, or just jealousy. There should never be hate for tie guy #3.
It's simply a matter of being over-dressed. Being over-dressed can be just as bad as being under-dressed. If you show up in a tuxedo to your friend's low-key, casual birthday party, it'll cause the same kind of tension. It doesn't matter if someday you want to be this friend's best-man at their wedding('dressing for the job you want', so-to-speak), it's just odd to draw attention to yourself in this manner. In fact, it might backfire if people think you're trying to steal attention from your friend(who is the person everyone at the party wants to see, not you).
If you dress in a tie when others are wearing shirts and jeans, then you're calling attention to yourself. People are going to question why you're wearing a tie, especially if you've been a shirts and jeans kind of person for a long time. Why now? What changed? Why are you doing this? What's your goal? blankip's answer covers that well enough so I won't go into it more.
As for "dressing for the job you want", there's a few things to remember:
If you're a lowly minion(like I am) at the start of your career, then dressing like the VP of Engineering doesn't make much sense. You don't jump from Junior Developer to VP of Engineering just because you put on a suit. There are intermediate steps between the two positions, and you'll have to traverse those first. Doing so will require more than cosmetic changes; you'll have to prove you can be successful at the next level each time you want to move up.
Over-dressing for the actual part is also bad. Let's say the next step is the VP of Engineering for you. If the current VP of Engineering and other VPs are also walking around with shirts and jeans, then you're also implying that you know how to dress for the position 'properly' and they don't. If you really want to move up a step, wear the same kind of thing the next step wears. I only bring this up because you mention an office environment that seems really casual - no ties at all.
Another way to think about it: if your boss, and their boss, and their boss, and their boss - all the way up to the CEO - are all dressing casually, then you're not dressing for any of their jobs, you're dressing for the job you have idealized in your head. And that's where people start assuming you're interviewing for other positions. If you're not dressing for any position at the current company, the logical conclusion is that you're dressing for a position at another company.