Technologies are provided for filtering user's actions based on user's mood. User's actions may include online actions. To prevent “in the heat of the moment” actions, which a user may regret later, a mood based filter may identify a user action such as posting a message to a social network, a professional network, an email network, a blog, or an instant message network. An automatic system action may then be taken based on the detected user's mood. In some examples, the user's mood may be assigned to a numeric or alphanumeric category. Various system actions such as blocking or delaying the user action may be tied or associated to the user's mood category through one or more predefined, customizable rules. In other examples, a user confirmation of the user action may also be included in addition to the automatic system action.