to kill or not to kill, That's the question.

I have just killed an small insect walking on the wall. Have I done the right thing?   :?
First, I thought with myself I am right, because it enters my house, and will bother me, and I have no choice except killing it. Suddenly, another idea urges to my mind: does it enter my house, or I am in it's house.
Oh, I made a house exactly on top of his house.

Haaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!!!!
It means I should not kill animals any longer!!! even mosquitoes!!!!
Haaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!!!!