Ed doesn't like flowers.
Roy gives him flowers. He puts it in a vase. In a week or so, Ed throws them out because they already have withered away.
He doesn't like chocolates either.
Roy presents him a heart-shaped box, filled to the brim with chocolates. He eats it in less than ten minutes, and gets a stomach ache later on. Roy laughs at him, and Ed just throws the empty box at him.
Ed would rather have more of those special moments between them, and those words Roy says to him on an almost hourly basis.
He remembers the rough feel of Roy's gloves touching his skin, burning him in a way that the fire he makes can't ever match up to, and he feels Roy's lips on his, mouthing the words, "I love you."
At least those last longer than any bouquet or box of chocolates can.