Never has the idea of privacy been more important than in today's highly digitalized and connected world in which no one is completely safe from privacy abuses.
Yet, the more we fear these types of abuses, the more we expose ourselves to them, either recklessly or involuntarily. We post so much information about our private life online (where we're at, with whom, why) and even if we don't do it, our friends can't stand the temptation of tagging us or uploading group photos that include us. So, in a way, we don't have a choice, we simply have to be online because this is now the place where life is happening.
However, we can be more careful when it comes to storing personal information on devices that can also be used or accessed by other people. So, if you simply forgot to log out of your account and someone else has read your private messages (something that, most probably, happened to me a couple of days ago) you can say that out of recklessness, your privacy has been violated.
It is, of course, your fault for failing to protect your privacy by logging out of any accounts other people might access. However, this does not justify their behavior. If you leave your email inbox on your desktop, your colleagues shouldn't be reading your emails, if you leave your journal on your bed, your mother shouldn't start going trough its pages and the list of examples can go on and on, but you got the main idea. Going through someone else's private message or written thoughts is simply something no one should be doing. It's invasive, imoral, low and mean and it most often cause harm on both sides.
In short there are 3 main reasons why you should not take advantage of someone's unprotected private correspondence:
you never know what dirty secrets you might find and it will be your burden to live with them
you will most probably ruin or seriously damage your relationship with that person once they found out you've been going behind their back
you will put yourself in a bad position as these actions are simply a big no-no and should make even the proudest person blush
Summing up, no matter how close you are to a person or what rights you might think you have over them, you should never violate their privacy even if they were foolish enough to basically invite you to do this.
Pictures from www.pixaby.com