You'll feel deceptively comfortable with this person -- deceptively because the sense of ease and familiarity between you won't actually be the positive sign it seems to be. You'll feel as if your friend's basic energy, their personality, their sense of independence and individuality, are quite instructive for you. But in reality, their particular brand of independence and energy can only lead you backward, not forward.
Something within you is responding to them at a level of instinctive recognition; you'll feel as if they're significant to you, as if they have much to teach you. It's far more likely, though, that subconsciously, they remind you of a person or a relationship from your past. The problem, of course, is that like relationships, life should be about progress. This friendship could encourage you to stop growing and regress in subtle yet important ways. Staying in this relationship long-term will impede your forward progress in life, whether you realize it or not. Comfort and familiarity aren't worth the tradeoff -- moving away from the direction in which your soul is supposed to travel.