Deepseek is GOATed for me because of this. If I ask it if "X" is a dumb idea, it is very polite in telling me that X is is dumb if the AI knows of a better way to do the task.
I'm partial to the tone of Kimi K2 — terse, blunt, sometimes even dismissive. Does not require "advanced techiques" to avoid the psychosis-inducing tone of Claude/ChatGPT
Every other AI I've tried is a real sycophant.