Did they just enjoy your item, and leave a note?

Some people love to read, and do not want to leave something they have enjoyed reading without letting the author know they have enjoyed it. These are the source of many of your positive reviews that don't have a lot of breakdown with other feedback in them. Accept them, thank them, and move forward - they enjoyed it, and they wanted to let you know. Some might even have a little tiny bit of feedback and a lower rating, but I wouldn't worry too much, they are just passing through.

Are they seeking out review rewards?

Some people enjoy the review rewards, and so they leave reviews so they can earn them. As long as they aren't abusing the system by not actually reading your item and just leaving multiple reviews with the same exact words, usually exactly 250 characters, over and over - or just filling their reviews with junk to get to the 250 characters to get the rewards, these are also nice to receive. They tend to be reviewers that review quite a few items, and aren't much harm.

Are they intentionally trying to hurt your feelings?

Was the reviewer being intentionally cruel? These types of reviews can and should be reported. Usually, these reviews are 1 or 2 star reviews with ugly or cruel statements, with no real reasons for these statements. Oftentimes they are unrelated to the item itself and are personal attacks, though not always such. If anyone is intentionally going out of their way to be cruel, then that is not permissible, and these types of reviewers should be reported to the staff so they can be handled. Often, they do this in a private review so others will not be able to report it for you - you may have to do it as the recipient. But never let anyone be intentionally cruel to you, that is not anyone's right.

Or are they simply giving you feedback, even if it hurts just a bit?

Sometimes, even if the feedback isn't what we want to hear, or even if the stars aren't quite as high as we feel they should be, the intention of the reviewer isn't to be cruel. If the reviewer finds quite a lot within the item that they feel needs adjustment, and the reviewer gives powerful constructive criticism, a low rating of 1 to 3 stars might be given because they feel that the item needs quite a lot of work, and not because someone is intentionally being cruel. These stars exist in the rating system for a reason, and that reason isn't for someone to be cruel, it is because items sometimes do need a lot of work. There has been a stigma in recent years that receiving these stars is an insult, but it shouldn't be. One should always be able to edit, fix what is wrong, and then ask a reviewer to return to an item to look at it again and offer another review and change the amount of stars given.

However, realize that you have the right to disagree with your reviewers, too. You don't have to agree with everything they say is wrong, and you don't have to fix everything. Really, you don't have to fix anything. You are welcome to thank them for their feedback, and leave your item just as it is. I make this choice on a regular basis for several items I wrote for The Writer's Cramp - because I find that the beauty of those items is that I wrote them in 24 hours, and I leave them unedited, mistakes and all.

You should also realize, however, that arguing with your reviewer if and when you disagree will get you nowhere. Their opinion is just that - their opinion. And your opinion is yours. Try as you might, it is unlikely you will sway your reviewer to your side, because the item in question is very much yours, and the reviewer is less connected to it than you are.

Realize that how you respond to a review reflects on you, and can determine whether you receive more reviews from great reviewers.

If you act really negatively toward someone that worked very hard on a review for you, it will reflect badly upon you, not on the reviewer. Begging or demanding 5 and 4 star reviews is not received well. If someone believes you deserve 5 or 4 stars, they will give them to you. Some people give them out rarely, some people give them out very often. Whether or not you receive them depends on the person doing the reviewing, and whether they believe your work deserves it.