No matter how many times he transforms into Captain marvel he almost always forgets how tall he his in that form. In his regular body, he is a small malnourished preteen. He barley reached into 4'8-4'11 feets at the age of 10 and reached 5'1 feets at age 12. But when he transforms he turns into a giant form of his father. He is taller than the rest of the justice league. He believes that he is 6'2 but in reality he's even taller that that. He has already reached 7 feet tall.
So when he tries to enter a room he always forgets to bend down so he would hit his head, he has to be bending down to even fit in a apartment room or sometime a house. Even so when he accidentally drops things in the floor he once again forgets about the table he his about to get hit on and ¡boom! He hits his head.
Being tall and champion gives you the enchantment of strength so, all items that he hold in his Champion form look supper small and delicate. That same goes to all living organisms he has been close, carried, and seen. They look small that sometimes he is scared to put pressure on them or things. When a civilian was needed to be carried away from danger he he make sure to focus on his strength.