Her laugh was different.
Sometimes it was wicked, other times it was a oddly cheerful giggle from taking down cloakers. The twisted giggle was his favorite sound and he couldn't place why at first. Houston just figured everyone had a sound they liked and that his was simply Clover's giggle. She must have caught on, she was always picking up on subtle hints. He noticed she'd go after the specials more that swarmed him.
It could have haunted him, but it was more calming that someone shouting over his shoulder about killing something. Houston didn't understand fully why announce they killed it, but then realized if a heist had gone loud it's better that way. If Chains wasn't on the job with them, Houston started shifted from staying by Dallas to staying by Clover. Wolf or who ever else came along could sit with his brother. He wanted to be around someone that seemed to understand his logic of gun and gear choices.
Even know when they were stealing the Diamond for the Dentist, he could hear her. That twisted giggled, almost muffled while he hacked the electrical box in the vault room.
He'd tell no one, not even her, that the sound he liked the most was that
twisted
little
giggle.