Can I pick your brain?
Nope. Nope. Nope. Nope. Nope. No, you can’t. This question comes from people who are looking for advice — basically free consulting. Of course, if someone wants to give you a free consultation, that’s their decision. But you should at least demonstrate that you’ve done your homework and you have skin in the game before you try to commit someone else’s time.
Ask this instead: “I’ve been doing research on this topic, and I know you know a lot about this area. Can you help me find the answer to some specific questions I have?”