During the fleeting and amorphous experience of fun, we are distracted from the self. Our self-definition, our concerns, our problems are no longer the focus. We distract ourselves from the constant clamour of the internal dialogue. This is not meant to imply that fun is unimportant or by any means "bad". Its ability to distract with short-lividness and superficiality satisfies an important underlying psychological need.

In contrast, pleasure is a deeper form of enjoyment. The main difference between pleasure and fun is its focus on an activity and a deep feeling of absorption. Pleasure, in this sense, is not short-lived. It may not even be spontaneous. It happens when ...

During the fleeting and amorphous experience of fun, we are distracted from the self. Our self-definition, our concerns, our problems are no longer the focus. We distract ourselves from the constant clamour of the internal dialogue. This is not meant to imply that fun is unimportant or by any means "bad". Its ability to distract with short-lividness and superficiality satisfies an important underlying psychological need.

In contrast, pleasure is a deeper form of enjoyment. The main difference between pleasure and fun is its focus on an activity and a deep feeling of absorption. Pleasure, in this sense, is not short-lived. It may not even be spontaneous. It happens when people are devoted to an object or activity. It happens when people try to make sense of themselves – explore and nourish their identities. The objects or activities an individual is absorbed by make a connection to his or her self. They become important, relevant.

Experiential and cultural connotations of fun and pleasure:
Fun - Pleasure
Distraction - Absorption
Triviality - Relevance
Repetition - Progression
Spectacle - Aesthetics
Transgression - Commitment

It was […] at the turn of the eighteenth century that the language required and developed the word fun in something like its current form. […] When […] class relations came to be organised around production and labour […], a “low cant word” appeared which signified the absence of seriousness, work, labour. When production is mechanised, when labour processes are rationalised, when time is ossified to demarcate work and leisure, the word fun appears as its correlative. Fun can be seen both as a resistance to the rigid demarcation between work and leisure and also as a means of reproducing that dichotomy.

Mark Blyth & Marc Hassenzahl: The semantics of fun: differenciating enjoyable experiences. PDF file.