I live in A but work at B. The two are 45 minutes apart and I could commute back and forth either by driving or by taking the bus. Every day, before going from A to B in the morning and before going back from B to A in the evening, I always do one same action that has different ramifications.
On day 1, I violated the law in A but arrived at B not in violation of the law. Later that day, I was not in violation of the law in B but arrived at A in violation of the law.
On day 2, I violated the law in A and I arrived at B still in violation of the law. Later that day, I violated the law in B and arrived at A still in violation of the law.
On day 3, I did not violate the law, at A or B, for the entire day. I was late for work, however.
On day 4, I violated the law in A and I arrived at B still in violation of the law. However, at B, I found out that the day was a holiday so I returned immediately without taking the action. Once I arrived at A, I was not in violation of the law.
What is the easiest explanation of what my action was before traveling between A and B?