Someone cuts in front of you in traffic. Before you decide anything, your hands grip the wheel and the words are already out. A message arrives in a certain tone, and your stomach drops before you have read the second line.
None of that was chosen. It happened. The tradition puts it plainly: most of the time we are not acting, we are reacting. Like a machine, something comes in and something goes out, and the one who could choose is never asked.
This is not meant to make you feel small. It is meant to free you. If your reactions are mechanical, they are not you. They are habits running on their own. And a habit you can see is a habit you can begin to change.
People often try to change their lives by changing their circumstances: a new job, a new city, a new partner. Then the same reactions move in with them, and the new life starts to look like the old one. The circumstances were never the whole problem. The reactions were.
So the work starts small. Not by stopping reactions, which is impossible at first, but by watching one happen from beginning to end.