A man decided to visit his friend. He had never been to his home. He didn't see his friend's car or any sounds of life, but he decided to knock on the front door anyway. He knocked and heard a voice come from inside saying, "Come in." The door was unlocked. He entered. Immediately, he was attacked by a vicious Doberman Pincer.
The man was being pinned against the wall with the dog at his throat. He called out to his friend but there was no response. Just then he looked up and saw a parrot perched near the ceiling. The bird said, "Come in."
The man was furious. He verbally attacked the parrot saying, "You stupid bird. Is 'come in' all that you can say?"
The parrot said, "Sick him."
Sometimes it's smarter to swallow your anger and keep your big mouth shut.