The extra daily social time of 1.7 hours in weekends raises average happiness by about 2%.

Often, the most enjoyable part of an activity is the anticipation.

Ten minutes of a smartphone in front of your nose is about the equivalent of an hour long walk in bright daylight. Imagine going for an hour long walk in bright daylight and then thinking, "Now I'll get some sleep." It ain't going to happen.

It doesn't take many observations to think you've spotted a trend, and it's probably not a trend at all.

A large portion of the weekend effects is explained by differences in the amount of time spent with friends or family between weekends and weekdays.

People like leaders who look like they are dominant, optimistic, friendly to their friends, and quick on the trigger when it comes to enemies. They like boldness and despise the appearance of timidity and protracted doubt.

Optimism is normal, but some fortunate people are more optimistic than the rest of us. If you are genetically endowed with an optimistic bias, you hardly need to be told that you are a lucky person - you already feel fortunate.