delusional
Someone who is not thinking clearly, or thinks something will happen that, in all likelyhood, will not.
Example:
guy1: So I'm thinking of asking Leah out. I think she might say yes.
guy2: Ummm, are you delusional or something?
guy1: So I'm thinking of asking Leah out. I think she might say yes.
guy2: Ummm, are you delusional or something?