I found a paragraph in this article http://www.linusakesson.net/programming/tty/ very apt at describing what Unix signals are like:

  In *The Hitchhiker's Guide to the Galaxy*, Douglas Adams 
  mentions an extremely dull planet, inhabited by a bunch of 
  depressed humans and a certain breed of animals with sharp
  teeth which communicate with the humans by biting them very
  hard in the thighs. This is strikingly similar to UNIX, in
  which the kernel communicates with processes by sending
  paralyzing or deadly signals to them.