Here's how Csikszentmihalyi describes flow in the interview linked above,
In the early seventies, I spoke with chess players, rock climbers, musicians, and inner-city basketball players, asking them to describe their experience when what they were doing was really going well. I really expected quite different stories to emerge. But the interviews seemed in many important ways to focus on the same quality of the experience. For instance, the fact that you were completely immersed in what you were doing, that the concentration was very high, that you knew what you had to do moment by moment, that you had very quick and precise feedback as to how well you were doing, and that you felt that your abilities were stretched but not overwhelmed by the opportunities for action. In other words, the challenges were in balance with the skills. And when those conditions were present, you began to forget all the things that bothered you in everyday life, forget the self as an entity separate from what was going on—you felt you were a part of something greater and you were just moving along with the logic of the activity.The entire interview is very interesting. I'm not sure I agree with/understand how he is using the term "evolution," but it's still interesting.
Everyone said that it was like being carried by a current, spontaneous, effortless like a flow. You also forget time and are not afraid of being out of control. You think you can control the situation if you need to. But it's hard because the challenges are hard. It feels effortless and yet it's extremely dependent on concentration and skill. So it's a paradoxical kind of condition where you feel that you are on a nice edge, between anxiety on the one hand and boredom on the other. You're just operating on this fine line where you can barely do what needs to be done.
I have definitely experienced flow a few times in my life; during cross-country races in high school, when first learning to be a compositor at work, occasionally while writing, and often while reading a challenging book. I also think I attempt to create the conditions for flow, while doing boring tasks that must be done by creating games to challenge myself (like how many lines of data-entry can I get through in an hour...bleh.), but this doesn't usually work.
I think, though, this is what we mean when we say that someone loves their work. We mean that they are able to enter into "flow" while working.
When do you feel as if you are in "flow"?
Later in the interview, Csikszentmihalyi says,
We are born with certain instructions to act, and then we are told by the culture how to act. And while we have to honor the reality of these things, at the same time, we have to reflect on the implications that carrying out these instructions would have.
There is the Hindu notion of karma, which should also be translated in modern terms, because it's true that everything you do, in a sense, has an impact on everything else. We are part of a system, and if we act in a certain way, it doesn't stop there. It will have an effect both now and through time. It will have an effect. So once you realize both that you're part of a system and that you are all these instructions, then you recognize that you have the responsibility of either endorsing all these instructions or trying to break out from them.
I really like the challenge in this quote; recognizing the reality of things, but at the same time seeing you have an active choice within that reality to continue as before or to reject your set of "instructions" in whatever way you can.