Well, without actually reading the specific 'the happiest boy in the world tagalog story', I can only guess. Maybe it tells of a boy who overcomes hardships with his positive attitude. He might be from a poor family but still finds happiness in the love of his family, the beauty of nature around him, and the hope for a better future. His innocence and ability to cherish the little things make him the happiest boy.
Since I haven't read the story, it's hard to say exactly. But it's likely that the main character is the boy himself. There might also be his family members, such as his parents, siblings, or grandparents who play important roles in his happy life.
In the Tagalog version of 'The Boy Who Cried Wolf', the story structure is similar, but the language and expressions are tailored to the Tagalog language and cultural context. This can add a unique flavor to the familiar tale.
Another theme is exploring the backstories of the characters more deeply. In the actual drama, there may not have been enough time to fully develop all the characters' pasts. Fanfictions can fill in those gaps, like delving into the character's family history or how they came to be the person they are in the drama.
Another place could be Wattpad. There are many Kdrama fans who post their fanfictions there. Look for the Snowdrop section or do a general search. However, the quality may vary, so you might need to sift through a bit to find the really good ones.
One great Kdrama to watch for a love story is 'Crash Landing on You'. It tells the story of a South Korean heiress who accidentally paraglides into North Korea and falls in love with a North Korean army officer. The chemistry between the lead characters is amazing, and the show beautifully depicts their journey of love across different cultures and political boundaries.