I was thinking about the following problem:
Suppose R is a ring s.t. every left ideal is also right. Is R commutative?
This actually continues the easier question:
Suppose G is a group whose all subgroups are normal. Is G commutative?
The answer to the latter is negative, since one can take the quaternion group of order 8.
Edit: One can indeed take a division ring as an counterexample. I am looking for something more interesting, in particular with some proper ideals.
Thanks
Not sure if this is satisfactory, but division rings only have trivial left and right ideals.
Therefore finite products of noncommutative division rings are counterexamples.