How/why creating *Figure object* changes defaults of plot?

I've notice that if I

(1) create a plot vs.
e.g.
plot([1,2,3])

(2) explicitly add a plot to a Figure object

e.g.
fig = Figure()
p = fig.add_subplot(111)
plot([1,2,3])

it looks DIFFERENT?!?

(2) remove grid lines and changes ratios
of axes to each other it appears.

how make (1) and (2) LOOK the same?

Chris