These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Wheres My Water
That One Level: "Interruption" & "Rinse Cycle" from the main game and "Aqua Tool" & "Make It, Break It" from Cranky's Story.
"Purple Lemonade". Even though it's an optional bonus, you'll need to be very good at your movement of the funnel and you'll also need luck for the ooze explosions if you want to collect all 3 ducks.