Like others, coming into this I was hoping for a resolution to Leon and Pob's story. I really enjoyed watching their relationship develop in Don't Say No and was disappointed that they didn't end up together though I appreciated the reasoning of it and was glad it wasn't something stupid that separated them. However, I ended up disappointed in this aspect. Though they are both in the special, they don't interact with each other at all, just multiple instances of barely missing each other, and their screen time is very limited. Here the reasoning for their continued separation is more than a little pathetic. Pob emailed Leon multiple times over those three years but Leon never replied and then talks about having lost the password for the email account a year ago. It didn't make much sense especially when password recovery is far from rocket science. There's a part of me that's hoping there will be another series dedicated to their relationship and this was a bit of a teaser for that. I hate seeing their story left unfinished.
In regards to the plot, well, there really isn't one. Despite the three year jump, there's no story progression. Leo and Fiat return to Thailand after studying abroad and basically just spend time with their friends before Leo starts his new job. There are some very sweet moments as well as one rather smoldering scene, but again, not a whole lot happening. I did appreciate the subtle changes in their characters though. They're still the same people but there is a greater maturity to both of them, especially Fiat. Their open communication and the little things they say show that both they and their relationship have continued to develop in healthy ways. I've watched several dramas where couples talk about their need to communicate and make positive changes that never happen so actually seeing that change was very refreshing. Their friends, on the other hand, are pretty much hilariously unchanged.
In conclusion, I wouldn't call watching it a waste of time, its short and sweet, a lighthearted escape back into well-loved character's lives, but if you're looking for any major changes in those lives or a larger continuation of their story, I'm afraid you'll be disappointed.