As discussed in Part 1 the quirks of our time-keeping systems can lead to "interesting" patterns in time series charts. Here's the example I used previously for ease of reference:

To summarize the significant bits of this chart in words…

Our ability to get by with every-day life relies on all sorts of estimates relating to time. We estimate the time it takes to get ready in the morning and set the alarm clock accordingly. When walking we make judgments about how long we think it will…