In my opinion, it is an easy answer :
Being a follower.
Yes, to follow blindly without listening to your instincts.
That road most certainly will lead to future problems and stresses.
Translating that into the fitness world, think about empty trends, silly group classes and all those fads.
People must be aware that the fitness industry has a lot of fads and empty promises.
So being a follower of the latest thing is not the way to go.
Question everything and above all, listen to your instincts.
How can most people destroy all their gains on their health journey?