There’s an interesting story making the rounds on the web this week: it’s about a graduate student  in Northern California who applied for an internship at Cisco, got one, --and then went on Twitter to muse aloud that she wasn’t too cool on Cisco, hated the idea of commuting from the Bay Area to San Jose every day, and was only considering the job because of the “Fatty Paycheck” attached to it.

Why she’d use technology to diss a tech company is beyond me but yup, you guessed it: someone allegedly  from Cisco saw the diss, alerted HR and apparently the offer was rescinded before she even made his first hated commute to San Jose.  She will now be seeking an internship with a  Fatty Paycheck elsewhere.  (In retrospect, she says her Tweet was “crass-sounding.”)

Which brings us to the Exit Interview. 

That would be the last formal interview you have before you leave your company, whether you’re downsized or dismissed or have found a better job elsewhere.  Not all companies do them, but a lot want to know how they can improve in the future.

If you had a good experience but found a chance for advancement at another company, let your almost-former employers know.  “I’ve really enjoyed working here, but it didn’t look as if there was much chance for a promotion soon. Company B is offering me an opportunity to move up and continue in the field, so I owe it to myself to go.”

If you had a terrible experience, let them know in neutral language.  Neutral is key.  Save the non-specific rant for your friends.  “You people are so racist!” doesn’t really tell the company anything useful.  Instead, consider this: “I’m going to Company Y because I didn’t feel the issue of diversity was taken very seriously here.  Given the markets we’re moving into, that seemed like a serious oversight.  I hope that changes in the future.  If it did, I’d love to come back one day."

You’ve told the HR person their lack of diversity was the reason they couldn’t retain you;You’ve indicated you’re moving to a company that does take diversity seriously.  And you’ve left the door open in case they get their game together in the future.

If that’s too up-front, or if you worry that years later you may be penalized for speaking truth to power, some business veterans have another approach:  Just say “thanks for the opportunity.  Wish you the best.  Bye.”  And be done with them.

Just don’t go ballistic, no matter how awful your time there has been.

It’s a small world, and since businesses keep buying each other and merging, the place where you decided to turn it out in the exit interview might be the place you end up working—without even changing jobs.

So in leaving a job, don’t be like that grad student in Northern California was in considering one.

Be professional.  Use professional, neutral language if you want to be on the record about company drawbacks.  And if you have to vent, don’t do it on a social networking site!

Karen Grigsby Bates is a Los Angeles-based reporter for NPR News.  She has been known to Tweet and use Facebook—discreetly!