If someone is fucking up, they are in the wrong position. People need to work for a living, and shouldn't be under duress constantly. It is up to them and their manager to find a position that is rewarding and engaging for them.

If they don't care, they are also in the wrong position.

It is no reason to not treat them with kindness. You don't have to blow them, but you don't need to be UNkind, as several have said below.

The only people I don't treat with kindness are people who are legitimately trying to hurt me and people I love, or promote hateful ideas with glee. People who are failing at their job need help.

And if they still annoy you, then I think the problem might be in how you view the situation. Compassion helps with anger. Try to think about why you are so angry, and if it really matters or helps to be so angry. Especially if you are not the manager. If you are the manager, consider that maybe the job isn't for you. You shouldn't be pissed at work all day!!