One natural choice for a center point of a convex polytope $P\subset\Bbb R^d$ is the average of all its vertices
$$c(P):=\frac{v_1+\cdots +v_n}{n}.$$
Call $P$ centered if $c(P)=0$
Question: If $P$ is centered, is its polar dual $P^\circ$ centered too?
This is true if $P$ has an irreducible group of symmetries, because $P$ and $P^\circ$ have the same symmetries and $c(P)$ is the only point fixed by these symmetries. This implies a positive answer to this question for simplices.
As it turns out, counterexamples are easy to find.
The trapezoid has its centroid in the origin, but its dual has not. Both facts are easy to argue for by geometric considerations.