Say no to sarcasm. Yes, it's okay as a funny aside during a dinner conversation with people you know well. But it doesn't belong anywhere else, and certainly not in a creative workplace. Categorically ban it from any place or space where you're endeavoring to bring something cool and new to life.
Sarcasm brings with it many ills. If I'm listening to your concept for a marketing tagline, and I sarcastically respond "That's great", I've just cut you down in public, which is not helping you get to a better place. And now you no longer trust me as a generative, open-minded person. Worse yet, the next time we work together, you've learned not to take my utterances at face value. So the next time I say "hey, that's so cool!", you're going to waste energy and time processing that statement to figure out my intent, as oppposed to taking it as a microburst of positive energy which helps push you forward.
We're all here to be remarkable. A broad commitment to being remarkable reduces the friction, smooths out the bumps, and amps up the energy we all need to continue bringing cool things to life. Sarcasm is friction. Plain old nasty, energy-robbing, friction.
Innovating is already so hard — so why add any additional things to get in your way, right? Just say no.