The phrase Keep your friends close but your enemies closer doesn't exactly apply to Minho. He wants his enemies to be as far away as possible from him. Aside from trust for Newt and Thomas, Minho is pretty much a lone soldier. The dude is out to survive, and he's not going to listen to anyone who's even remotely suspicious.
And, yeah, he has a lot of enemies. Even one of his fellow Gladers, Teresa, turns out to be one of his biggest enemies. And the great thing about Minho is that he isn't afraid to tell it to her face: "You shanks know more and remember more than anybody else. Teresa, I've never made a secret of it—I don't like you" (6.22).
Ah, what a gentleman.
But the thing is that Minho is a lovable character precisely because of how brutally honest he is with others. Now, this personality trait does unfortunately makes him narrow-minded, and he does tend to miss the point when it comes to important clues. When Thomas talks about his memory dreams, for example, Minho responds: "I don't see what that has to do with anything," Minho said. "Just makes me hated WICKED even more. Good thing we left, and I hope I never have to see Teresa's shuck face again" (22.3).
The number one thing that fuels Minho is hatred: he hates WICKED, he hates the world he lives in, and he even hates some fellow Gladers. Now, it's not always a bad thing to be like Minho. With a narrow-minded personality, you do know at least one person has your back: yourself.
Another reason why we should all love Minho is that this desire to keep his enemies far away means he's a man of action. Need someone to pull the trigger? Minho's your man. When guards from the Right Arm refuse to give any kind of information to Thomas and the gang, for example Minho takes control of the situation:
"I'm telling you, we don't know nothin'." The guy's face was pinched in anger.
"Fine," Minho replied. He fired the gun. (46.17)
Yeah, Minho's got kind of a trigger-happy, visceral personality, and yeah, it can get him into trouble as often as it saves him. Thomas sums up Minho's shortcomings when he says, "Minho was a liability. His temper was too short" (47.9).
Love him or hate him, Minho is crucial to the survival of not only Thomas but also of humanity. He's constantly beating the klunk out of guards and soldiers, and he's the chief interrogator. Without Minho, the kids probably would have all been toasted by Grievers in Book One.
By the way, Minho is simply hilarious. He's sarcastic and snappy, and boy, is he a joker. In a dark series such as The Maze Runner, we crave some humor so that we're not putting the book down and moping all day. With Minho, we can always get a good chuckle in.
Before he goes through a simple airport detector, for example, Minho gives a nice quip that pretty much epitomizes his sense of humor: "'If I don't see you on the other side,' he said in a sappy voice, 'remember that I love you'" (23.39).
The Gladers are all placed in a horribly depressing situation. There are crimes against humanity being committed every second of their lives, and yet Minho is still able to look at things with a bit of humor.
A little dark humor never hurt nobody.