"I need a full, stable reflection. So no rivers, no wet walls, I probably couldn't see out of the reflection of a wine glass..." And so on and so forth. There's nothing condescending in Strange's tone: he's just explaining this in a matter of fact tone of voice.

He's craning his head at more of an awkward angle to get a better look at Beau. "Honestly, I chose this reflection so I can talk to you. After all, you probably have questions, and I probably have answers."

And Strange is egotistical enough to assume he has all the answers!