Despite its dismal box office performance, I thought Dum Dum Dum was a fairly well-crafted romantic comedy. It did have a slightly tedious second half, and the big conflict between the parental units seemed a little implausible, but I found it much better than the other Madhavan movie that came around the same time and fared quite well - Minnalae.
Dum Dum Dum is essentially a showcase for Jyothika's brand of acting. She is generally accused by her detractors of playing the same role over and over again, and these detractors are usually right. However, I'd say this is a movie where it is not a disadvantage.
The plot involves the two (Madhavan and Jyothika) being stuck in an arranged marriage neither of them wants, so they do all they can to have it called off before it gets solemnized. As luck would have it, none of it works, they find themselves drawn to each other and then an actual fight erupts and... you can fill in the rest.
Anyway, one of the strategies adopted by Madhavan to try and break the alliance is to approach his prospective father-in-law directly and persuade him not to give any dowry. So, when the parental units are meeting to discuss the details of the marriage, the man does as Madhavan says and refuses to pay a dowry. Jyothika isn't aware of this strategy, so the entire thing is a surprise to her. The way this scene plays out is quite nice - there's actual dialogue being spoken, but the real conversation is the unspoken one, between Madhavan, Murali and Jyothika. All three of them do such a good job with their eyes that you are never in any doubt about what each of them is thinking.