1. His childhood wasn't a very happy one. When he did force himself to think back to when he was younger, all he could remember was his Da shouting and slapping, and his Ma crying and crying and crying. Then Da left, and his memories got happier after that.
2. He loved Dean Thomas, his best friend. He loved him so much, and there was nothing he wouldn't do for him. So when Dean came into their dorm, grinning, and announced he was dating Ginny Weasley, well, his world came crashing down once again.
3. He was never ashamed to be Irish, never had been. His heritage was one of the most important things to him, and he was proud of the beautiful island he came from.
4. He still shudders when he thinks of the most horrid year of his life; Seventh year. The middle of a war, the Carrows ruled the school, he-who-must-not-be-named was getting more and more powerful, people were dying...and Dean wasn't there by his side. Was Dean even alive? He didn't know. That was the worst part, the uncertainty.
5. He never did tell Dean how he felt about him. A few years after the war, he went and married some Hufflepuff girl that he'd known from school. She was a wonderful girl, and he loved her very much, but she wasn't Dean.
Nobody was the same as Dean.