Why did Isaiah cry "Woe is me" when he saw the Lord?

Answer: He had unclean lips

"Woe is me, for I am ruined, because I am a man of unclean lips… for my eyes have seen the King, the LORD of Hosts."

“Then I said: “Woe is me, for I am ruined, because I am a man of unclean lips dwelling among a people of unclean lips; for my eyes have seen the King, the LORD of Hosts.””— Isaiah 6:5 (BSB)