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.
Alternate Character Interpretation: The Tree's love for the Boy is unconditional, but because the Boy is never said to give the Giving Tree anything in return, and doesn't seem to notice or appreciate the sacrifices the Tree is making for his happiness, some readers find the Boy to be very unsympathetic, which in turn makes the Giving Tree's sacrifice into glurge.
Glurge: The story is supposed to be a touching ode to the selflessness of a parent's unconditional love for their children. However, in highlighting just how selfless that love it, the Tree's sacrifice and the Boy's neediness can come across as rather creepy to some readers.
Tear Jerker: The story is (intentionally) both heartwarming and sad. We cry in happiness for the selfless spirit of the Giving Tree even though we feel sad that she has sacrificed everything about herself to express that love.