It's said that 80% of the lifetime of a project is spent on maintenance. If your code is unreadable, you're bound to be wasting a lot of time for whoever is maintaining your code, and inevitably, you will make them think evil thoughts about you.
From what I've seen, though, most teams of programmers (or even a whole company, sometimes) have a document or something explaining the code conventions and styles they adhere to. It is therefore quite easy on your first day of working there to input their rules into your IDE and just have it auto-format your code so you won't have to worry about it. Even better, you can probably find someone who is willing to "export" their prefs file so it's just a matter of a few clicks until all the code you'll ever write at that company is formatted perfectly.
That being said, you won't always have access to these team-specific conventions (say, for instance, in an interview). It is always a good idea to follow some basic conventions that make sense. Depending on your language, a good idea would be to Google "yourLanguage code conventions" and read up on the basics. What's important in the interview situation is that you follow some basic guidelines and have a formatting style that you stick to. If you make the bracket after an "else" statement on the same line once and write it on the next line another time, you're probably telling the interviewer that you don't really care enough and/or you don't have enough experience that one way has become a habit for you.
