It is rude to yell at a co worker.
Alex's disabled co-worker keeps messing up at work.
Alex wants the co-worker to work better.
Alex explains to his co-workers what he's doing wrong at work, and how he can improve.
Alex yells at the co-worker to stop messing up so much.
Alex's co-worker works more efficiently in the future.
Alex hurts his co-worker's feelings.