All of Am Yisrael were standing by Har Sinai when they received the Torah from Hashem. Moshe was in shomayim and the Yidden trusted he would return to them. They were afraid -- they were petrified, but they didn't run away. All Am Yisrael stood and didn't turn their backs and run away. They stayed and bore the fear because they knew Hashem loved them beyond a doubt. This love kept them standing in place even though they were overwhelmed with fear. They thought they will die with fear. All the Yidden stood and waited for the nissim that Hashem would bestow on them. They stood at attention in complete subservience to the G-d that they loved in return. They loved beyond a doubt. They loved with all their hearts. All the Yidden were glued to their places in love and service to their Creator. All the Yiddin were glued. All the Yidden were stuck to their creator. They were one with him at that moment and unable to move. They were glued to their Father in Heaven. They were one being, one klal, one coloney of people only serving one G-d. They had nothing else on their minds but Him. He was the focus of all their attention at the time. All their devotion and all their love. No one could distract them.
When Am Yisrael left the Har Sinai after the open revelation of the Shechina and Hashem's presence, they got shaky and fearful. They felt insecure and worried. They felt abandoned by their Lover. They needed the closeness of their Lover continuously after that to keep them intact. They could not be without it anymore. They felt what being one means and couldn't leave their Lover behind. They needed that show of love constantly and regularly in small doses in order to continue their existence. All the Yidden felt it and all of them needed it. All of them together missed it and as a unit were rebellious before Hashem and created the egel hazahav. All of them as a unit became insecure and made a mistake. They didn't know that Hashem is still there. They didn't know that Hashem would never leave them. They didn't know that it's temporary and He will return to them in forty days with the Torah. All the Yiddin together sinned in their oneness. Oneness can trip also. Togetherness can also make mistakes. Oneness doubles the feeling of rightness. One must be careful that the decision made in unity should be the right ones, should always be the will of Hashem and not the will of self. Yes. One must be careful to do what is expected of him and not his ratzon. He must do what is cut out for him to do and not his decision.