There are several synonyms for the phrase "works oneself up." It can be replaced with "get agitated," "get worked up," "get worked up into a frenzy," "get riled up," or "get upset." These phrases all describe a person becoming emotionally charged or worked up about a particular situation or topic. Working oneself up can often lead to stress and anxiety, for this reason, it's usually better to try and remain calm and level-headed in situations that may provoke such emotions to avoid potential negative consequences.