What are the biggest mistakes engineers make when they interview?

(Reposting my own answer from Quora, with some edits)

This answer is directed towards software engineers, but some of the tips apply equally well to other engineers.

Biggest strategic mistake, by far, is that candidates interview with a loaded agony of getting a job, instead of simply demonstrating who they are.

When you agonize about getting that job, you are nervous, you judge yourself during the interview, you amplify small mistakes.

But when you go there to simply explore, simply to solve a fun problem, to see how far you yourself can get, and to respect the interviewer’s time, you will notice that most fumbling starts to go away. You’ll take control of the interview then, because you’re not agonizing.

Like Bryan Cranston says: there is power in that. If you haven’t watched the following clip, it’s worth watching, over and over again. He is talking about actors and audition, which is very similar to interviewing:

The other big strategic mistake, is actually made before the interview viz. they under-estimate the amount of preparation required. They walk into an interview like it’s a lottery ticket, and they are surprised why they didn’t win it.

There are some other big tactical mistakes also:

1. Not realizing that half the interview is about your communication and behavior in the interview. Had communication and behavior not been important, the companies would just send you some coding problems to do, and generate an automatic offer letter after test-cases passed. But no company does that. Why? Because they want a conversation, and you have to be ready for an inspiring conversation.

2. Trying to go for the most optimal solution from the get go, and overlooking to give the brute force. If you can’t think of an optimal solution, and you don’t give a brute-force solution either, the interviewer keeps wondering if you even understood the problem.

Remember, that an interview is a date; it’s not a standardized test. It’s about showing who you are, and not about agonizing about fitting into someone’s mould. You will make far fewer mistakes when you recognize the true nature of the beast.