a tall glass of water
A boring, tall guy who makes you want to fall asleep. He’s the kind of guy who just stands there and says nothing.
That guy at the bus stop is a tall glass of water. He’s so tall and so boring.
My uncle is a tall glass of water. He’s tall and he just talks about his job all day.
That guy in my math class is a tall glass of water. He’s tall, he’s boring, and I can’t stand him.