  Deformed Special Relativity (DSR) is obtained by imposing a maximal energy to
Special Relativity and deforming the Lorentz symmetry (more exactly the
Poincar\'e symmetry) to accommodate this requirement. One can apply the same
procedure deforming the Galilean symmetry in order to impose a maximal speed
(the speed of light). This leads to a non-commutative space structure, to the
expected deformations of composition of speed and conservation of
energy-momentum. In doing so, one runs into most of the ambiguities that one
stumbles onto in the DSR context. However, this time, Special Relativity is
there to tell us what is the underlying physics, in such a way that we can
understand and interpret these ambiguities. We use these insights to comment on
the physics of DSR.
