Often, a person who calls himself an intellectual is actually just a pretentious ninny who cares more for his or her own ego gratification than living the so-called "life of the mind".
If they claim to be an expert on a certain topic (art, science fiction, computers, philosophy, high literature, or whatever) but can provide no real insight into the topic other than their own unsubstantiated opinions, they're a snob. Feel free to ignore them.
If they offer high-minded definitions of "intellectual" that boil down to: "All the TV shows/ movies/ authors/ clothing/ operating systems I like are what all intellectuals like," then they're a dork who wants to pretend to have an IQ. Feel free to ignore them.
If they like to talk about how smart they and their friends are and about how stupid and worthless "normal" human beings are, then they're an elitist. Feel free to kick their ass.
Here's a funny and true story which you may enjoy. When I started college many, many years ago, I was able to get into the school's honors English course. On the first day of class, the professor asked everyone to introduce themselves, and tell the class who their favorite authors were. I'd set myself up in my traditional seating place at the back corner of the room, so everyone got to introduce themselves before I did. Every single person in the class -- all of them freshmen, none of them over 20 years old -- started listing off writers like Plato, Aristotle, Dostoevsky, Moliere, Wordsworth, Voltaire -- all great writers, but not the kind of guys you normally read for pleasure and not the kind you read when you're that young unless you're wanting to impress people with how smart you are.
So when it was my turn, I stood up and loudly announced my favorite authors -- Stephen King and Agatha Christie. Ye gods, did they all act stunned. I'd brought sin into their House of Learning! Popular writers? Read by commoners? Everyone acted like I'd peed on a nun. I must admit that I'm proud that none of them spoke to me for the rest of the semester.
But I graduated on time. Which is more than you can say for 90% of the students in that class. Most of them had dropped out or flunked out before their junior years...