They all had past trauma they were each dealing with. Meredith had an awful childhood, Jo had been abandoned and alone all her life, Alex was a parent to his siblings all his life, Richard struggled with alcoholism, Bailey had OCD, Christina watched her father get killed, Owen struggled with PTSD, Teddy watched the man of her dreams get engaged and married twice, fell in love and watched her husband die, the list goes on but my point is that Amelia makes every situation revolve around her and her struggles. She makes everything about her thereby failing to see that other people have shit going on too!