Your friend may inhibit your imaginative side if they try too hard to get you to focus, ground yourself in reality and stop taking your delicious flights of fancy. If you let them have too much of an influence on you, this could be quite a restrictive, depressing effect. But if you can strike the proper balance, their influence in your life will be a stabilizing one.
Similarly, your imaginative side (or what they may perceive as a general lack of common sense) could hit all their buttons, pushing them into a space of needing something concrete, something quantifiable, just to feel secure. But if you can hit that balance, you'll help them to relax a little, reminding them to let go of cold, hard reality from time to time in favor of the pleasures of fantasy. Also, you can teach them to trust their intuition as well as those factors that they can see, touch and measure. You two can be a very good match on these levels if you try.