What is Zen? Huangbo says, "Sweep out the dung that's been piling up in your head for the last twenty years." Linji says, "Just stop seeking and see what's there." Also, "Wake up to what's pulling the strings. Seeing, hearing, tasting, &c. -- it's only one light, imaginarily differentiated." Joshu says, "Amitabha Buddha." Tsunemoto says, "Zen is just getting rid of the discriminating mind." Rujing said, "Zen study is the shedding of body and mind." Hakuin says it's waking up to Reality from the pitiful ego-delusion.
The ego-delusion is just that, a delusion. It's the firm belief that everything in phenomena somehow relates to, opposes or favors "me." Or that I know what others don't know, and must convince them. It makes one uneasy. Drop it, and experience great ease!
Or, if you can't drop it in an instant, thoroughly investigate what this I is. Where is it exactly in the body? What color and shape is it? What are the signs that it exists? Does it begin and end? When you walk into a room, do you carry it in, and when you leave do you carry it out? Who is this "you" that's looking for the "I"?