I have a coworker who would often ask me questions relating to his work. But what I find annoying is him constantly interrupting me to finish my sentences only to get it wrong all the time.
One instance, I purposely frowned my face and told him "please listen" after about a 3-second pause. This still didn't give him any idea to just shut up and learn.
I ignored him for a particular period of time and would say "I don't know...but try this", or "how does the boss think this is possible?" while knowing fully well the task is possible.
This approach affected his performance as he got a lot of bad reviews from our boss. And in some cases, I would be asked by our boss to assist him, then telling him there isn't solution for the problem to avoid enduring the frustration would reflect poorly on my performance too.
How do I handle this coworker as ignoring him clearly does not help as I will be officially asked to help him?