I was kind of happy that they bought up the shart thing. Please don't get me wrong here but the whole bet part was a bad incident in their life. Naina has whole-heartedly forgiven Sameer for that, but it is something that will take time for her to forget. That's human brain, it just can't erase stuff overnight. That scene actually gave a realistic touch to the whole scene. I actually loved the zikr of shart. It will take time for them to forget it, or there are chances that they won't forget it ever as the shart was an important part in their story.