Wuppo

Happiness is your HP, the maximum can be raised to 200. Based on the English guide .

[+1] Go into the hollow on the other side and talk to the frightened Wumgarden
[+1] Talk to the elevator operator several times (Wumhouse)
[+3] Talk to the fat man in the jacuzzi (Wumhouse) - it may take several in-game days, for each long dialogue +1
[+5] Listen to 5 stories of an old man (Wumhouse)
[+1] Complete Willie's Quiz (Wumhouse) - it's a Wumhouse with a birdhouse hat
[+3] Find your painting on the 2nd floor (Wumhouse) - appears after the artist’s quest, you need to shoot his canvas with a bazooka with yellow paint
[+5] Defeat the boss Brum (Wumhouse) - appears after defeating the dust boss
[+5] Eat 5 pieces of cake (for each +1)
[+2] Ride Megakrank (Wondersplenk)
[+1] Ride Topdrop (Wondersplenk)
[+1] Play Jolly-Boing (Wondersplenk)
[+1] Buy a glowing hat and wear it at night (Wondersplenk)
[+7] Fortune Teller (Wondersplenk) - requires a minimum of 29 coins, just keep talking to the fortune teller in the park until you become friends (this gives the associated trophy - A Friendly Future)
[+1] Blow bubbles on the island (Blusser Islands) - from the amusement park we sail across the sea to the left until we come across a vuma blowing bubbles. Let's join him.
[+1] Get a coffee hat (coffeehat) and leave a positive review about it (Popocity) - located almost at the very beginning of the city in one of the houses, just start the dialogue after receiving the hat
[+1] Continue asking Allesdenker "How is your day?" (Popocity)
[+2] Participate in debates in the city hall for the first time (Popocity) - you need a special hat with a bell, you can buy it in a local store or at the entrance to the hall, 64 coins
[+1] Talk to Spuifje several times in the city hall (Popocity) - this is pink voom
[+1] Help the presenter at the radio station (Popocity) - you need to kill the Knefts on the roof, after which the radio presenter will be able to work again. Located in the very top right corner of the location.
[+1] Laugh at the prisoner making jokes in the prison (Popocity) - visit the prison another time if the desired prisoner is not there.
[+1] Work in a factory (Popocity) - you need to stand on a free slot and jump with your partner until the bright yellow light comes on, and then talk to the head of the factory
[+1] Help Pieter start his own business (Popocity) - you need to complete about 5 newspaper deliveries, after which the employee will tell you that he wants to start his own business. After this, you will need to run to the city hall and wait for the debate on his request. At the debate, support this decision, then return back to Pieter. It is advisable to do this before reaching 100,000 credit in the city (otherwise debates and delivery will be unavailable)
[+1] Ask fisherman Hendrick Visser about work (Popocity) - you just need to start a dialogue with him.
[+1] Sell the caught kneft to a snack bar (Popocity) - you need to buy small hooks (look like cloves) and fish until you catch a dead kneft. After that, we go to the diner (to the right of the city center) and talk to the seller.
[+1] Talk to Denksnavel in the underwater observatory after defeating Breevis (Popocity) - it will open when the credit counter starts working again, that is, you need to go through the drillhall and get to the location with fnakkers, then the townspeople will run back in panic and the city will start again collect credit. Then the opportunity will open up to finish all the things in the city that you missed.
[+3] Open the model of the universe in the Redav Kned's Guest House location (available after solving the riddle) and talk about it with your bird Denksnavel (Bliekopolis)
[+1] Talk to your bird next to the ancient drawing (Bliekopolis) - this drawing is located to the right of the place where you break the passage in the wall with the catapult. Immediately after breaking the wall, you go to the right and see steps - here you need to pull out the bird and start a dialogue.
[+1] Give Fnakker guard a piece of paper and open the secret passage (Bliekopolis) - the piece of paper falls almost at the very top of the location, just below the boss Chef Fnaquere. Next, you need to go down (just above the place where you received +1 for the ancient drawing) and give the piece of paper to the hungry fnakker - he will open a shortcut door for you.
[+1] Get to the other side of the world - get it automatically at the location with the last boss.
[+5] Find all films in the Wumhouse location
[+5] Find all the films in the Wumgarden location
[+5] Find all the films in the Tunnel location
[+5] Find all the films in the Wondersplenk location
[+5] Find all the films in the Blusser Islands location
[+5] Find all the films in the Popocity location
[+5] Find all the films in the Bliekopolis location
[+10] Watch all the films - happiness is given only for some, but watching all of them is required for another achievement. Hardly to miss.

I recommend doing this together with the trophy for beating the game in insane mode - max HP will be very useful there.