Do you feel guilty when you kill insects?

I never kill insects actively. I avoid using any kind of fly-killer type chemicals because they indiscriminantly kill everything (even ones you are not aware of). In addition, they tend to be bad for human health too. We put mothballs in our pianos because otherwise the moths would destroy them. Moths would eat the felt which the dampers are made out of. The sprays kill the spiders, which eat the moths and other annoying ones (such as flies). Even though I find flies annoying, I never hit them. I just wave my hand around to chase them around and I try to "direct" them towards a window or door to get them outside the flat. Even if I do not like their presence, I do not feel it means that I should kill them. They are just doing what comes naturally to them (generally trying to find food). In my opinion, they do not deserve to be killed for that. Even if they are spreading disease, they are not doing so intentionally. They almost certainly have no idea that they can make someone else unwell by walking around on the food they want to eat.