Depends on the bug.
Stuff like ladybugs, beetles or butterflies I'll try to avoid killing if I spot them.
Mosquitos, ants and flies on the other hand will be terminated on sight if I find them in my house. I do leave them be outside though.
Seeing a Mosquito indoors actually automatically makes me look for anything nearby to kill it with, and if there isn't anything... well a couple days ago when I hopped under the shower, and looked up to adjust the height and saw a mosquito... nothing around to squish it with.. so I just flattened the palm of my hand and swung hard. My hand was sore.... but there was a dead mosquito stuck to it so I consider it a victory =D
IQ tests are flawed and ultimately meaningless.