Only focusses on the emotions and personal experienced of the individual (external factors also affect wellbeing e.g. social relationships, finances, work, and cultural factors)
Experiencing negative emotions (rather than trying to rid of them) actually has significant impact on lasting happiness (by learning to develop resilience through negative affect)
Idea of being able to research happiness from a scientific point of view seems very limited as self-report measures (done through questionnaires) is the basis of this model and these measures specifically assess explicit attitudes (subjective and can therefore be biased)