According to Wikipedia, colliders are used as a research tool in particle physics by accelerating elementary particles to very high kinetic energy and letting them impact other particles. Analysis of the byproducts of these collisions gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it. These may become apparent only at high energies and for tiny periods of time, and therefore may be hard or impossible to study in other ways.
According to Washington Nationals’ rookie Bryce Harper, when asked about his shoulder colliding with Brett Lawrie during last night’s victory over the Toronto Blue Jays:
Crap, I hope I didn’t piss him off. He’s a big boy.
Shoulder barge to Scott Lewis for the GIF.