Why an installation ?

Because there's just no other way to go.

Installations and Performance Art (cybervirtual or not -- see Yacov Sharir's work) are in my humble opinion the best way to convey emotion. A space can create a sense of rejection or acceptance, touching can enhance this emotion still better than most affordable sensory devices and immersing yourself fully in the arena of the artist's creativity, fully, mind and body together, can lead to a stronger connection between the creator and the crowd.

Here's a brief list of a few performance artists whom made history in this field. (very brief.)

Chris Burden - famous for having his friend shoot him in the arm on stage in the 60s.

Vienna Actionists - Body performers... gruesome food and paint all over their bodies, rituals with animal blood. More Austrian Art Stuff & Stuff.

Yayoi Kusama - uses spots to camouglage the human body or make the body stand out in environments.

Krzystof Wodicsko - video projections on public buildings using images about the controversies of border towns.

Joseph Beuys - The German master was a dynamic prophet of the economic, social, environmental, political and cultural problems. Education was key to him. A Recent Beuys Exposition.

An Interesting Essay about Austrian Avant-Guard Performance Art

Previous Installations about Anger:

An interactive piece on The Anger of Loss by Stephen Wilson, an
eminent figure the Media & Performance Arts. Check his work at SF State University