Tamaki loved roses.
It was a well known fact, and whenever he said it out loud to anyone with any attempt at seriousness they tended to just laugh at him. Of course you do, Tamaki. Everyone knows that.
Because of that, Tamaki had long ago given up trying to explain his obsession with them. Thus, it was a great and pleasant surprise for him when Haruhi, wide-eyed and curious, asked him straight out why he loved them so much... and listened.
"They're like..artistic representations of humanity," he started, haltingly. "There are so many different types of roses, and they each need their own type of living conditions to prosper. They have all sorts of different petal colours and leaf shapes. Some grow only one blossom at a time to a bush, and others have huge communities. Some are always crawling and reaching for new places and new things to touch, while others are content to be master of their own patch of soil. All roses have thorns and can be hard to get close to, but even so they are all beautiful. Even when they're wounded or dying, they're beautiful."
Tamaki walked over to the nearest table and pulled a long-stemmed pink rose from the arrangement. "This one reminds me of you, Haruhi. Its thorns aren't very big, but they hide among the leaves so you don't see them until you're already too close. You don't mind being around others, but your true mind you keep to yourself, preferring to stand alone than be just one of a multitude." Walking closer, he snapped off the greater part of the stem and tucked the remainder behind her ear. The flower settled into her hair like it was meant to be there, petals unfolding to tangle in her hair.
Haruhi stared at him in fascination. "I see," she said quietly, and faintly blushed a familiar colour.
Tamaki smiled. He had many reasons for liking roses.