Starting from seventh grade, when school changed from home rooms to separate teachers and classes, I would say I have had at least 100 teachers, instructors, professors and TAs during my academic career. And with the exceptions of the coaches teaching gym class, I would wager that my grade in that class showed a firm correlation with the teacher's ability to draw in the students' interest. Now, keeping in mind that this was decades ago in a sub-par school district, and teachers had far fewer tools and resources to work with. Their main tool was literally their presentation. They won people over with, in so many words, their academic voice.
That being said, I have had several teachers who were, indeed, masters of their subjects - even carrying doctorates in chemistry and biology - yet bored me senseless. They didn't talk about their field work, they didn't put their passion into the lectures. They talked. They explained. They would offer the boring DNA lecture that interested nobody. However, their TAs talked wide-eyed about touching extracted DNA and feeling like they were holding life's codebook, and everyone felt that moment with them. Lectures were, at times, grudging requirements, but those TAs made molecular biology fascinating with their passion.
(For the sake of brevity, I will not discuss the broad spectrum of voices in my statistics classes. However, if boredom could be weaponized, I know some professors who had plenty of ammunition.)
With writing, we might have a fascinating story with deep, rich characters, but the first thing the readers will pick up is that voice. Without some spark, the rest of the piece is an uphill battle. Here's a simple exercise to promote that voice. Whenever you write a scene, some dialogue, even a description that really clicks; that really lights up your mind, go to the beginning of your work and see if that first paragraph or sentence has that same feeling. Go to some place in your work that feels weak and put all that positive writing energy into touching it up. When you write a sentence you know to be great, take that moment of magic and start spreading it around. Energized, impassioned writing is infectious, so there's no reason for you to hold back on it. And definitely make sure that your opening section gets as much of that energy as possible.
Oh - and maybe give a shout-out to the teachers in your life. If you think writing is tough, imagine what it's like to teach writing. Or history. Or biology. Or statistics...