While I get Heather's frustration with Derek about the smoking, I feel like she didn't communicate that very well. She had a very different idea/definition of what occasionally meant than Derek. It also sounded like Derek meant smoking one day out of the week which Heather took as he actually meant was 100% true. Like I said, she just didn't communicate that very well it seemed and it came across very wrong to Derek.
See also
Awards | FAQ | User Ratings | External Reviews | Metacritic Reviews