Teaching a practice can also be a hindrance if it becomes one's identity. To be a spiritual teacher is a temporary function. I'm a spiritual teacher when somebody comes to me and some teaching happens, but the moment they leave I'm no longer a spiritual teacher. If I carry the identity of spiritual teacher, it will cause suffering.
This is why very often you find educated people in the media who look at spiritual books but they are so identified with their thought process, they don't get it. They write reviews or articles and they miss the whole point. They can't see the essence. It's not their fault; it's not them personally. It's the human condition and its mind-identified state. And intelligence in itself doesn't help. You can have two or three Ph.D.s; it doesn't get you any closer to spiritual realization. In fact, you might be more distant.