Rock paper scissors says:
"Always throw rock" is effective until your opponent figures that out. Once they figure you out, they're always going to throw paper. Then you'll throw scissors to as your strategy to counter their strategy...
Worse, you may have a "tell" and they'll know what your throwing each time.
The only way you can remove your opponents ability to get an advantage over you is to pick randomly. Grab your phone and refresh the rock, paper, scissors generator before choose what to throw!