It is often said that one of the best things about Twitter is that it updates in real time, and that when things are flowing well it is not unlike being at a party, or at least a reasonably lively meeting. But there are two sides to every coin, and it is worth taking account of the fact that immediacy can make things very hard to take back, particularly when the information you have posted is sensitive, and/or is reported quickly by other people in such a way as to make you look stupid or expose something you would rather not have said or done. 

If you are in the jaws of a negative mood - be it sad, depressed or angry - then it is possible that you will make the mistake of saying something that you will later wish to take back. If you add alcohol into the situation, as many do, then it lowers the inhibitions which would usually prevent you from saying such things. Sitting in front of the world's most immediate information exchange, you can easily go over the line and do something idiotic. Posting personal details about an ex, making unwanted advances to another individual, or just saying something that makes you look like a moron - that sounds bad, yes? 

Now imagine that what you say is re-tweeted by someone either innocently or maliciously. You can delete your own tweet if you regret it swiftly, but it is still there in another person's feed. Put simply, if you don't want it to be common knowledge, don't Tweet it.