replying by not

How do you reply a reply that is either irrelevant, nonsensical, or downright stupid without resorting to mockery?

I can't. So I am extremely silent when that happens. Or you can also say that I'm... speechless.

backchat

Are you tempted to say something that'll put me in an uncomfortable position?

Please don't. I might regret it.

losing nothing

You can't lose what you've never had, right?
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Right?...