If you have multiple user accounts on your Mac but don't want to use the Fast User switching functionality, here is a small trick to quickly access them.
First step: SSH to your local machine and port-forward port 5900 (where VNC listens) to 5901 (can be anything you want):
1 ssh -NL 5901:localhost:5900 localhost
Now open the Screen Sharing tool and enter 'localhost:5901' as your destination. You will get the familiar login screen where you can choose another user and view their Desktop. All without logging out your current user!