Love and marriage are wonderful arenas in which to place a character. We are most likely to risk our morals and beliefs while in love. Betrayal gives tremendous insights into a character as well.
A house with any kind of age will have dozens of stories to tell. I suppose if a novelist could live long enough, one could base an entire oeuvre on the lives that weave in and out of an antique house.
WWI is a romantic war, in all senses of the word. An entire generation of men and women left the comforts of Edwardian life to travel bravely, and sometimes even jauntily, to almost certain death. At the very least, any story or novel about WWI is about innocence shattered in the face of experience.
I have spent many hours on the beach collecting sea glass, and I almost always wonder, as I bend to pick up chunk of bottle green or a shard of meringue white, what the history of the glass was. Who used it? Was it a medicine bottle? A bit of a ship's lantern? Is that bubbled piece of glass with the charred bits inside it from a fire?
As a novelist, I remain interested in the notion of a single reckless act and its consequences.