Maybe I should say most people are interesting. At some point, you will come across a person that is 'vanilla' plain, but not if you know what to look for. Everyone has a story. Everyone has a life. Everyone has had occurrences in their life, and those occurrences are great stories. Sometimes, it's the person's manner of speech that may put you off, but the story usually never does.
It's all in how it is told. The key is to get the person talking about something they WANT to talk about. This is not the weather or sports. I'm talking meat. Get to the meat of the person, to what trips their trigger and you will find an interesting person with an interesting story. And the boring speech usually fades to reveal the person underneath.
Usually, the good stories are the ones that tell you one of two things. One- something about the person you never knew before or Two- something about the world you never thought of.
I never thought I was an interesting person. But I am. Very much so. And this is not ego or self-confidence talking here. Nope- I actually have led a boring/struggling/normal but interesting life (for instance, did you know I was a carney?). None of which comes across on my blog. When I talk, I enunciate and pronounce things in weird ways. I emphasize certain words. I say EYEther not E-ther (either). I talk with my hands. I get quiet and speak low, or I get LOUD and large.
All to make the story more interesting. Because really, what is a story for if not to teach and or entertain the listener?
So next time you run across someone you believe to be plain and vanilla, talk to them. Find out their story. It could be more enlightening than you think.