I think that Hamlet is acting wierd because it is part of his plan to get revenge. He is planning to put on a play infront of the king, a play replaying his fathers death. He is going to to watch his uncle and see his reaction. He wants further proof that the ghost isnt the devil and that his uncle did kill his father. I think that they way he acts aroiund people is just an act to go along with his plan to get revenge. Although he is upset about his fathers death he channels that anger into rgetting even. I think that when he is by himself he is more relaxed and isnt as crazy, He reflects on himself when he is alone. I think that we are going to see that his acting crazy is all an act to get revenge on his uncle.