Yeah, when I had to stop dancing--an activity that gives me a flow experience every day--for weeks because of a twisted foot tendon, I became a mess of anxiety, and even resorting to singing sessions wouldn't quite give me my "fix", or fix me so to speak. Likewise, it's not about having to stop programming, it's about, for example, having to stop working on a project in which you have lots of daily momentum and flow. I think it's a proper addiction. Now if it's just half-hearted programming, nobody misses it much.