"It'll pass" or "it'll get better" or anything else referring to nonexistent hope.

Or, from a therapist/social worker/whatever, "what would help you right now?" when I clearly don't know the answer.

Oh yeah, my favourite. "It's your depression." Yah, duh. That helps.

Or "You're looking better" or "I can see you're improving" or "I can see you're getting better" when you're not and just pretending really hard.