Do you stop reading an email if it asks you for a "quick favor"? I don't, but I kind of dread what's coming!
What about someone who starts off "I would like to introduce myself." Yes, I delete that one. It's someone I don't know asking for something I don't want to do, so that gets the trash button.
Here's an article about 11 bad ways to start your email. Honestly, the author comes off as kind of a d**k, because yeah, we're all busy, but you gotta at least let people reach out to you.