I'd add: if you don't feel like working, don't. Sitting there in a cycle of pretending to work and then distracting yourself is worse in every way than just stopping and doing something else.
Even in a single-person startup we often pressure ourselves to conform to some semblance of a normal schedule. But I find myself much more productive with the work-when-I-feel-like-it policy.
I agree. For practical reasons of coworkers and family, we have decided to try a stricter scheduled work day. But it must go both ways; After the scheduled working hours, we shouldn't work.
Even in a single-person startup we often pressure ourselves to conform to some semblance of a normal schedule. But I find myself much more productive with the work-when-I-feel-like-it policy.