Teens say the darndest things, and their words can come back to haunt them far beyond getting grounded for the weekend. This is especially true when a think-they-already-know-everything-ager posts something shady on social media that they can’t walk back when they grow up and come to their ever-loving senses.

The internet never forgets and tweets, Facebook posts or even Snapchat videos they thought would disappear – can have devastating effects. Like when a recent high school grad realizes that their first-choice college ran a quick Google search on their name, found some offensive posts and rescinded their admission. That’s happened at Harvard, Cornell, Marquette University and many schools in recent years.

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Also bad? When a fresh-faced college grad gets to the interview phase for a new job only to be cut over a Facebook photo. “I was in an interview and (they) checked my social media pages, saw a picture of me enjoying a drink upon disembarking a cruise (which, by the way, I usually never drink) and accused me of being an unreliable alcoholic,” Sean Sullivan, who now works in the PR industry, wrote in an email.

Whether fair or not, perception is a big deal. In the same vein as updating your transcripts or resume, cleaning up your social media presence is a requirement for college admissions and job hunting. Here are some big red flags to look for on any Twitter, Facebook and Instagram timelines:

• Posts about sensitive issues: Free speech is a right, but freedom from the impact of your words isn’t and a recruiter or would-be manager could easily dismiss you as a candidate over incendiary comments, even if they agree with them. We’re all passionate about various social, political and environmental issues, but a harshly worded Twitter post isn’t changing anyone’s mind in your favor and it could cost you big time.

• Offensive comments about individuals or groups: A joke that you made in a Facebook post in 2015 might have seemed mild at the time, but standards for what is acceptable have changed dramatically. Even if you didn’t mean to offend, the same language you used back then might sound very different today and it’s better to be safe than sorry.

• Party time: Sure, a 30-second video showing you conquering a two-story beer bong might seem awesome to your friends, but your future boss might not be so impressed. Posting over-the-top content for everyone to see probably isn’t going to help your case when you’re college searching or job hunting.