Why?

Why are cockroaches such big insects? It is hard not to notice them.

What can't insecticide kill them? I had once sprayed half a can of Bygone on a cockroach and miraculously it survived the attack and flew (albeit in zig-zag motion) out.

Why do they like to crawl around aimlessly? It gives me the creeps.

What do they hope to find? I have kept my place clean.

What's worse is, why can they fly?! Flying cockroaches are the ultimate horror because you never know when they may just bump into your face. With them around, who needs horror films?