What's the worst cold outreach you've ever sent?

I'll go first. 200 cold emails, 3 replies, 2 of them angry. One guy replied just to tell me to never contact him again.

Spent a while thinking I was just bad at selling. Turned out I was emailing people who'd never thought about my product, while other people were publicly asking for it on reddit and I never saw those posts.

Curious what's worked for everyone else. Has cold outreach ever actually worked for you, or is it just something we all do because we're told to?