The most dangerous way to lose time is not to spend it having fun, but to spend it doing fake work. When you spend time having fun, you know you’re being self-indulgent. Alarms start to go off fairly quickly.
And yet I’ve definitely had days when I might as well have sat in front of a TV all day — days at the end of which, if I asked myself what I got done that day, the answer would have been: basically, nothing. But the alarms don’t go off on the days when I get nothing done, because I’m doing stuff that seems, superficially, like real work. Dealing with email, for example. You do it sitting at a desk. It’s not fun. So it must be work.