What is the significance of the groups other than pure autistic pleasure of composing cayley tables, figuring out associativity rules, etc. What do I care if my little imaginary group is isometric to some other group? What is so special about the klein-4 group? Why do I need to care about isomorphisms and homomorphisms and what not? I mean it is a cool concept especially the fact they are closed under some arbitrary binary 'operation'. Meaning that at least I don't pollute the environment when working with my group. But they remind me of a TV set I once found in a dumpster that I really wanted to rip it apart to see what's inside but by mom didn't let me keep it. Do I need groups? Do they work like a drug to distance yourself from reality?