Ah, the eternal struggle of email validation. Junior devs think it's just "check for an @ sign" while seniors know it's an eldritch horror that makes grown engineers weep.
The flowchart perfectly captures the painful truth: email validation is never a simple yes/no. Even with an @ sign, there's a universe of edge cases lurking in the shadows. Is the TLD valid? Are those Unicode characters legal? Did someone seriously put quotes in their email address?
Pro tip: just send a confirmation email and be done with it. Life's too short to write the perfect email regex that will inevitably fail on some obscure RFC compliance detail from 1982.