It's all about structuring the event:

Daniel Kahneman, Nobel Prize winner and author of Thinking, Fast and Slow, has shown that your brain really remembers only two things about an event:

1. The emotional peak

2. The end

Via The Paradox of Choice: Why More Is Less:

Nobel Prize-winning psychologist Daniel Kahneman and his colleagues have shown that what we remember about the pleasurable quality of our past experiences is almost entirely determined by two things: how the experiences felt when they were at their peak (best or worst), and how they felt when they ended. This "peak-end" rule of Kahneman's is what we use to summarize the experience, and then we rely on that summary later to remind ourselves of how the experience felt. The summaries in turn influence our decisions about whether to have that experience again, and factors such as the proportion of pleasure to displeasure during the course of the experience or how long the experience lasted, have almost no influence on our memory of it.

So how can you game the system with this information and use it to be happier?

Structure events so that the peak is great and the ending is great.