This one is sort of different from the others. It's darker, set later in my timeline of events for Jamie than most of the others. I've purposefully kept things vague. Enjoy!
…
"Jamie, hurry up!" James yelled, hammering on the door to the only bathroom in the small house. Behind it, he heard the unmistakable keening scream of hot water running from a shower head and splashing down onto the tiled cubicle floor.
There was a watery scuffle, before a muffled answer of, "Just a few more minutes!"
James groaned in frustration, before hitting the door once again. "You said that ten minutes ago!" he shouted back. "Come on, I'm all sweaty from work!"
"Just wait, would you?" the 15-year-old yelled in return, sounding extremely annoyed and even angry.
"Fine," he spat, settling himself darkly against the floral wallpaper of the opposite wall and rueing the day he'd stupidly decided he was fit for parenthood. He was obviously rubbish at it. Why had he yelled at her? In his experience, yelling never helped anyone. It was probably just built up frustration; things hadn't been to good recently, and Jamie acting like she was a completely different person didn't help. He knew it was partly his fault; he hadn't been there her when it had mattered most, and he hated himself for it.
As a distraction from the anger that currently welled up inside him, he took a sudden interest in the flowery wallpaper; he had chosen it when they'd first moved in, although he'd never, ever tell Sirius that. The old one had been a horrible yellowy green that had had reminded him of vomit, and had been soon replaced with the this pale blue one that was decorated with white flowers; buttercups, carnations, daisies and, most importantly, lilies.
Lily would know what to do, he though dejectedly, sagging against the paper, his head in his hands. Lily would know exactly how to be a parent to Jamie. If Lily had been there, she would have had everything sorted, and they could all go back to being a happy family. But Lily wasn't there.
There was a whistling sound as the water cut off. James took several minutes to compose himself, a scathing remark about lateness and wasting water on the tip of his tongue. The door quickly opened with a crashing snap, and a glaring Jamie wrapped in a bathrobe and with sopping wet hair emerged.
"There you go," she snapped venomously, turning with a swish of her now short black hair and pounding down the hall to her room. Droplets of water hit James' face from this movement. He opened his mouth, sneering to reply, by which time she had reached her room. With as much animosity as she could muster, she turned again, fixed her high-beam glower upon him, and said, "And for your information, I was washing my hair!" Then the door slammed, and James once again sagged back on the wall, tears in his eyes.
He forgot all about his shower after this; eyes red, he wandered downstairs and out the door, not once looking. A long walk followed, in which he thought mostly about white flowers, especially lilies.