If there is an identifiable problem, create a constructive environment with someone who can help remedy the situation. Micromanaging boss? Underperforming teammate? Set up a meeting to exchange feedback. To make sure it doesn't feel like a one-sided attack, share what you think is working well, what you think could be improved, and allow them to do the same for your performance. Since you expect them to take your feedback seriously, take theirs seriously too.
Fruitlessly venting can put you in one of a few situations: (1) your boss overhears you complaining, (2) your team thinks you're whining or dislike your negative attitude, which makes it harder to work together, or (3) your coworkers also start engaging in the negativity, which just feeds the toxicity of your environment. When you're in the office, the best thing you can do is to remain positive in the face of hardship.
Finding that "talking it out" is too difficult, either due to the person you're having a problem with or your own shyness? That's fine. Always closing your eyes to prevent yourself from rolling them while you're in the office? We can't always help it.
5. Learn to let it go
You can't control other people, their actions, or the outcome of a dinner with multiple cooks in the kitchen. When things go awry, learn to take a deep breath, tell yourself that things could be worse, and help yourself move on. Holding onto negative thoughts builds up in your brain and can make a bad situation feel much, much worse. Remember to let go of the negativity, and you might realize your environment is not as toxic as you thought.
This is a hard one to confront. Before you throw up your hands and quit your job, make sure that you aren't the main source of toxins at work — or the negativity could follow you forever. A good way to do this is to ask your boss or a trusted colleague for specific feedback on ways to improve your performance. If they seem to think that you have significant room to improve, it might be time to reflect on how you can improve your work demeanor.