The difference

Scientist: "I need you to make me a green laser."

Engineer: "Okay. I can make it a rainbow laser!"

Scientist: "No. A green laser."

Engineer: "A green laser than can make square, sawtooth, and sine waves?"

Scientist: "No. Just a laser."

Engineer: "...a laser than can shoot up to forty beams at once?"

Scientist: [looks into camera like they're on The Office]

CONVERSELY...

Scientist: "So, have you smashed together those protons yet?"

Engineer: "No."

Scientist: "What's taking so long? All you have to do is isolate a bunch of protons from heavy water, accelerate them to 95% the speed of light in a 40 km circle, and then aim them at each other! It's easy!"

Engineer: [looks into camera like they're on The Office]

Really important question!

If you're a human and you subsist on drinking other people's blood, is that cannibalism?