depends on the goal of the workout. some workouts a negative split is great, other workouts like a long slow distance run and/or intervals, you may want to keep flat splits. in my opinion, negative splits are great, but don't lay off in the early miles just to obtain negative splits, you should work hard (if the workout demands it) and strive for negative splits by putting yourself out there.
Where are we going?? And why am I in this handbasket??
right now. somewhere. somebody is working harder than you.