Dissatisfied: Deprived of satisfaction; displeased; disquieted by the feeling of the insufficiency or inadequacy of something.
Unsatisfied: Not satisfied in respect of something desired; not having obtained all that, or as much as, is wished for.
In laymen's terms? To be dissatisfied, you would be displeased, unhappy, or upset with a person, thing, or situation. To be unsatisfied, you would feel like you want more with something usually abstract. For example, if I go to a restaurant, I can be dissatisfied with the service. Maybe the waiter never refilled my beverage, or perhaps refilled it too often (oh, I'm terribly picky with service). I could also be dissatisfied with the food. Let's say the tofu went bad and it was sour. That would warrant being dissatisfied or displeased with my meal. Now in the same context, I could also be unsatisfied. Maybe there were only three pieces of tofu in my noodle soup and I was hoping for at least five pieces. Tofu isn't abstract, but you get the picture. I wanted more but couldn't have it.I know it's kind of confusing--it certainly is to me still. Something that can help is when you see either word in text, just pause and think about how the author used it and try to understand the meaning.
