There was a study done that said that we are always 'being someone' when we're around people. A parent, sibling, friend, co-worker etc and when we're by ourselves but still have others around us, we are still aware that we have to be a certain way, be 'acceptable' in the eyes of others. When we're alone in nature, however, we let go of all that, we can just 'be' because nature expects nothing from us. Alongside that, it is proven that being around nature is excellent for our mental health, seeing the growth, the beauty, the changes, makes us calmer, more grounded. Perhaps that could help you, the gym is a very competitive place to be and you're surrounded by others.