For example, you read a story where a set of twins are the main characters and their names are Joe and John. Do you find yourself mixing it up sometimes?
Do two main characters having similar names bother you?
If you can't answer with a simple yes or no, if there are factors to it, such as, "It only bothers me if the characters are portrayed as identical, and have practically identical names..." then use the comment feature.
In other news.. I can't seem to check my email. This annoys me to no end.