You've made it through the first couple of rounds of job interviews. But you know that sooner or later you'll have to answer those behavioral interview questions that you dread most. These questions seem designed to trip you up, or get you to say something bad about yourself or someone else. For example: "What is your biggest weakness?" It just doesn't seem like there's any good answer to a question like that.

Or you may be hiring a new employee. You know you'll ask these behavioral interview questions, but you don't know exactly what answers to be looking for.

To help you get the most out of your next interview, the folks at Rooftop Slushie, a site that matches job-seekers with insiders at big tech companies for mentoring and referrals, reached out to hiring managers at Google, Facebook, and Amazon. They asked for these managers' suggestions for answering these persnickety questions -- and they got some great ones.

You can find the full text of their answering suggestions here. These are my favorites.

1. "What is your biggest weakness?"

To begin with, a Facebook manager advises, don't use this answer to humble-brag, as in, "My biggest weakness is that I work too hard because I never want to give a second-best effort." 

Instead, a Google engineer advises, pick a weakness that really is a weakness. But it should be a weakness that you are working to improve, and it should be a weakness born of choosing between competing priorities. 

An example of a good answer might be: "I'm working to learn to delegate better, which is hard for me because I like to be a hands-on leader." 

2. "Why do you want to leave your current company?"

This is the kind of question where it seems like honesty will never help you. An Amazon manager advises that even if the new position offers a higher salary or better perks, you're better off not mentioning them.

Instead (even if it's a lie) say that you don't want to leave your current company, in fact you're very happy there. But you saw their job description and you were intrigued -- it seemed like it might be the perfect next step in your career. And so you are here, hoping to learn more about this wonderful-sounding job.

3. "What do you do if you disagree with your boss?"

Managers from Facebook and Amazon agree: You should talk about your current boss with respect and empathy, acknowledging that he or she had a legitimate point of view. Then you should describe how you used data to persuade your boss that your approach was the right one.

For example, your boss decided to focus on acquiring new customers, but you wanted to put more effort into selling more to existing ones. So you started a small project to pitch new sales to existing companies using an email campaign. The existing customers turned out to be a better source of revenue than the new ones and your boss wound up thanking you for finding a better way.

Next time you're faced with a tough behavioral interview question, use these approaches to craft the perfect answer. And if you're the one asking the question, consider these insights while evaluating the answers you get.