That one's my favorite. You can't defend against it, it just shuts down the conversation. Odds are, you aren't doing it wrong. These people are usually suffering from Dunning Kruger at best, or they're paid shills/bots at worst.

Best part of being dumb is thinking you’re smart. Best part of being smart is knowing you’re smart. Just don’t be in the iq range where you know you’re dumb.