There is a big difference between realistic and real.
The more your characters are vivid and the more your readers will care for them.
But if your characters look and sound like your neighbors, nobody will like them, be interested in their story or sympathize with them or even find them remotely interesting and even less captivating. Admit it, your life, my life, is boring; you and I are boring from the point of view of fiction. So it makes sense that the more your characters resemble someone real, the more boring they get.
Your characters cannot be you or someone you know unless you exaggerate their traits and turn them into super heroes.
Fictional characters are blown out of proportion, are larger than life and have incredible gifts we were never given.
Think about James Bond or Harry Potter. What do they have in common with most people? Nothing.
Fictional characters are created to live in people’s mind, out of people’s imagination, doing things that involve magic, extreme courage, superhuman feats. They are interesting, fascinating, captivating, funny or dreamy because they are idealized people, people you dream to meet one day or people you admire.
Wait a minute and consider. Superman comes from another planet. Spiderman was given magical powers by a rare spider. Jane Eyre has made her way into the heart of a rich and powerful man. The Pretty Little Liars are entangled into a web of a Machiavellic criminal.
Not only would fiction characters be exaggerated and outrageous or incredibly lucky, but also all their actions will be logical and understandable, well-motivated and even their lives (experiences, diplomas, achievements) will lead to where they are now. Fictional characters do not know sheer luck and accidents. But do you?