Okay, I'm still seeing some people here who don't quite understand how this works.
You do NOT have to create a Google+ account to leave reviews. The fact is, when you have a Google account for Android, by default a Google+ account is created for you. What's happening now is that your reviews are being linked to that account.
So what you are failing to realize is that even if you never leave another review in the play store, YOU STILL HAVE A GOOGLE+ ACCOUNT!
As long as you are using an Android device with a Google Account (ie. Gmail) you also, BY DEFAULT, have a Google+ profile page.
You can delete your Google+ account, however it is not clear whether or not this just deletes content you have posted to Google+, but leaves the "profile", or if it deletes your profile page as well.
You also have the option of deleting your Google Profile, but I have no idea how this will affect any other Google products you use, or even how it will affect the use of your Android device.
To get there, log in to Gmail. Go to your account settings (See your account name/icon in the top right corner? Click on your icon, then click on Account). > From the Account Overview page click on Google+ from the menu on the left side. > Scroll down to the bottom and you will see a section called "Disable Google+".
Again, you will have two options, deleting Google+ content, or your Google profile, and I have NO idea what that will do to your other products. You have been warned.
Once more, to those of you saying you won't leave reviews because you don't want to have a Google+ account... even if you never leave another review, you still have a Google+ profile page.