What's the best thing you've learned from a stranger on the internet?

Not from a course.
Not from a book.
Not from a YouTube creator you already follow.

I'm talking about something a complete stranger shared online that genuinely changed how you think or work.

For me, it's usually an unexpected comment, a thoughtful forum reply, or someone generously explaining something they didn't have to.

It makes me wonder how much valuable knowledge quietly exists online without ever reaching a wider audience.

What's one insight from a stranger that has stuck with you?