To point out the flaws or not to point out the flaws?

Here's the scenario:

You've gone out with someone three times. Each date is a disaster partially because your date has some personality traits that are undesirable by almost anyone's standards (cheapskate, arrogant, etc.). Yet, this person thinks there is nothing wrong and continues to pursue you with zeal.

So you have finally determined that you don't want to see the person anymore. The person is still calling you and texting you and you are stuck with the task of letting them down. The question now is how and what you should say.

With option one, you would just say you are no longer interested and say something like there was just no chemistry. With option two, you might consider making the person aware of their personal flaws because, in your mind, this is a service to all potential suitors for the person.

Which option would you choose? When you decide to stop dating someone, do you believe they need a full-blown explanation? Which factors do you believe play a role in selecting your options?