What does a bad potato taste like?
The flavor is sort of tangy and sour, not what you would expect from potatoes. It’s possible that they were rotten. It’s also possible that they were pickled and you just didn’t like the taste because it’s not something you are accustomed to.
Is it OK to eat bitter potatoes?
Because of the bitter taste and appearance of such potatoes, solanine poisoning is rare outside conditions of food shortage. The green indicates they have been exposed to cold or light, they are making chlorophyll when this happens an alkaloid develops it is bitter, can be toxic but the rest of the potato is fine.