Teiresias was
a) The Blind Seer of Thebes, who, depending on which myth you're reading, was either blinded when young by Athena (the patron goddess of Athens) for seeing her naked whilst bathing, then given the gift of prophesy when she relented after Teiresias' mother pleaded.
The other (more interesting one in my reckoning) claims the he saw two snakes coupling, and was turned into a woman, until he saw the same two snakes coupling. After this experience he was called upon as an arbiter to an argument between Zeus and Hera, about who got the most pleasure from sex. Teiresias claimed women get '9 or 10 times more' pleasure. This statement annoyed Hera so she blinded him, but won Zeus the argument, so he gave him the gift of prophesy.
He was a follower of Dionysus, the god of wine and vines and being very pissed, (top god to worship in my book) for a while and famously warned the Pentheus not to cross Dionysus,advice which was not heeded, leading to the death of Pentheus. He also predicted the greatness of Hercules (aka Heracles in some texts), and revealed the fact that Oedipus had commited patricide
or
b) My online persona, a shortsighted, know-it-all, who drinks too much ...