I think it depends on the individual and how they see work, how one aspect of their life leaks into another another and so on.
Speaking personally I know that even when I'm stressed at work I still know the difference between tasks carried out as part of my job, and tasks carried out which are potentially similar, and which may be being carried out in a work setting, but which are not work.
Don't get me wrong, if I feel work is going badly, doing something else and being OK at it is almost certainly a good thing, I just think that doing something work related and doing it well is probably better.
Speaking personally I know that even when I'm stressed at work I still know the difference between tasks carried out as part of my job, and tasks carried out which are potentially similar, and which may be being carried out in a work setting, but which are not work.
Don't get me wrong, if I feel work is going badly, doing something else and being OK at it is almost certainly a good thing, I just think that doing something work related and doing it well is probably better.