A long time ago, when I was much younger, I had no fear of cockroaches. You just stepped on them, or smashed them (preferably with something covering your hand, but yes, I actually did smash them bare-handed).
Then a friend's house ended up with TONS of them. Seriously, the floor had a weird shimmer of their movement. I'd never seen so many alive and moving in one place. IT.FREAKED.ME.OUT.
I then entered a stage of being afraid of them and not killing them. It was so bad that I made my students do it. Something about them running away and crunching just made my stomach tie up in knots. Also, the fact they could be *anywhere* at any moment, just gave me the heebie-jeebies. In fact, I ended up with dedicated cockroach killers in my classroom.
However, this year, I have a new teaching partner. Pam, one of the first days we worked together, picked up the cockroach in a cup and flung it outside. She went on to explain that, to her, they weren't that much different than the crickets she'd had to catch when her son had reptiles.
I'm not afraid of crickets (or grasshoppers). Suddenly, I thought I could do it.
So when I saw one in my class, I stepped on it. Sure, I shuddered at the sound and the subtle shift from hard to soft. But I did it. Then I did what I always could do, I picked up its dead body with a Kleenex and threw it away. It was hard, but I'd done it.
Now I've killed about four. It's still hard. However, I think that I must push past this fear. It's not rational. There's no reason for it.
I admit though, I have to talk myself into it each time. I'm not fully over the fear yet.