Hi Spongeleaf,
According to the Apple Watch User Guide, the following are instructions or functions of clicking the Digital Crown (found on page 61):
"To return to the Home Screen from an app, press the Digital Crown once, then press it again to switch to the watch face."
and
"Open an app from the App Switcher
1. Double-click the Digital Crown, then turn the Digital Crown to scroll through your most
recently used apps."
These functions cannot be reprogrammed to perform differently through standard settings. Ensure that you are only pressing the Digital Crown a single time to return to the Home Screen while in an app, or double-pressing to access the App Switcher function.
Regards.