You: "It's just Instagram."
Employer: "This image does not reflect the morals and values of our company. We don't need someone like this on our team."
We live in a generation consumed by the notion that if we didn't snap it or take pictures of it, it did not happen. While it may be fun to broadcast some of our wildest moments, every experience should not be shared with the public. Before posting something, think about if it is something that you would want everyone to see or just your friends. If you opt for the latter, send it to their inbox or DMs instead.
Although your page may be private, there is not such a thing as privacy on the Internet. You may delete something off of your page, but it is never deleted from the online cloud. Due to that fact, you should be mindful of those you friend on social media. Remember that someone is always monitoring you and you would hate for someone to report one of your posts or profile to a current or future employer for inappropriate content.
PROTECT YOUR IMAGE! Remember that once your image is tarnished, it is hard to clean up. Your online space, including, but not limited to: things you post, your profile pictures, the language you use and the things you share, should be clean enough that you would not be ashamed if your parents or employer accidentally stumbled across it. Additionally, perspective is reality. Even if you "didn't mean it that way," a person is going to interpret it the way that they want to. Essentially, your social media accounts is a representation of you and just as you should try to portray your best self to others in person, your accounts should reflect your best you.