Confusion...

Do you ever wonder why God puts certain people in your life? Perhaps they are frustrating, nay, angering, at times. Maybe they force you to think differently about things. Possibly they challenge you directly or in roundabout terms. Other times, these people may be your friends, help you out, make you laugh, or give you some encouragement. But all the while, you just can't figure out the reason for that particular person and the assortment of feelings you have related to them. Anybody know what I'm talking about?