I'm still fairly new to the realm of voice acting. I started pursuing it seriously just a couple years ago, and I'm far from what I'd call a 'professional'. I started in the realm of monster voice acting due to my background in metal vocals, but I've been expanding my territory into regular voice acting as of late.
It's during my regular voice acting recordings that it dawned on me what really makes someone a great voice actor. I'm capable of making a line sound near professional quality. The emotion I put behind the line can be top tier, and when people hear it they're very impressed. But the thing is...most of those lines took me 30+ takes before it finally got to that point.
With professional voice acting where they're recording in a studio, they will generally have only a couple of takes to get a line right, due to the fact that they're generally paid by the hour. Thinking that, it made it finally click what separated a 'decent' voice actor from a 'great' voice actor.
A decent voice actor may be able to eventually produce a line quality enough to rival a great voice actor, but a great voice actor can produce that quality line right off the bat. Realizing that really humbled me. It made me realize that I really do have a ways to go as a voice actor yet. It makes me excited though, cause now I finally have a goal to aim towards!
And I'm someone that also suffers from a severe stutter. I could easily blame that for why It takes me so many tries to get a line right, and maybe that's partially true, but I know it's not completely right. Even if I can say a line without stuttering right off the bat, I usually won't have the right emotions down till at LEAST my 10th take.