We are humans, and it is normal to get stressed sometimes, be angry, or feel bad. Actually, this is what sets us apart from animals, rationality. It happens to me, it happens to you, and this is something ok. But, tiredness, stress, and other bad feelings affect our productivity a lot. If you don't know how to avoid that, there are many different ways to recreate your mind. For example, to recharge my batteries, sometimes I can have a brain dump, and it is beneficial.