Sharing your computer with other people can be detrimental to your personal settings. Unlike a lot of services and features you can customize, Google+ offers the ability to back up your account data in case of tampering.
Once logged in to Google+:
Step 1: Click on your profile menu in the top-right corner (the one with a miniature version of your profile picture) and choose Account settings.
Step 2: You will see the Account overview area. Now select Data liberation from the menu on the left side.
Step 3: Click the Download data button near the top of the next area that loads. You can back up all data or just choose to back up Google+.
Step 4: After double-checking the services you have selected on the Takeout menu (ha!), click Creative archive to make the backup. You may be prompted to log in again, and then your backup(s) will start processing.
Step 5: Click the Download button in the lower-right corner of the processing area to save the backup to your computer.
Now you can be sure that your profile, stream, and circle settings can be reloaded in case any unwanted changes occur.