A/B tests & feature flags, what do you love and what do you hate?

Hey folks,

I m a huge fan of feature flags and technics allowing to ship features more efficiently to the users.

And I m very interested to hear your stories on how you use these tools to ship better features for your audience.

What is the most interesting metric that you rely on and that tells you "hey, this is what we should provide to the users"

Let me know everything about your experiences!