The French put up potatoe fields guarded by the military, but the soldiers were instructed to not catch anyone trying to steal the potato plants. Thus making people think it was valuable, and cultivate it.

In sweden they introduced it, people cultivated it but ate the leafs and got sick so they went on a rampage to kill the persons who had introduced them to potatoes.

BTW the Hachis Parmentier is a dish named after Parmentier and it's delicious!