Especially when used pejoratively. Used to described someone who is easily pleased by small things that are very common or that people can get easily.
possibly complaisant - If you are complaisant, you are willing to accept what other people are doing without complaining.
Example: Because John is too complaisant in his willingness to please others, people often take advantage of him.
Example: Hector was a poor manager because he was too complaisant, being pleased with his staff working, but not considering the quality of what they did.
I think uncritical will fit well here.
accepting something too easily, because of being unwilling or unable to criticize.
Example: An adoring, uncritical audience
An answer to the title question is undemanding.
From M-W Learner's Dictionary:
undemanding adjective ... not demanding:...
b of a person : not expecting much time, attention, effort, etc., from other people : not difficult to satisfy
He is an enjoyable, undemanding guest.
I have three options that come to mind.
responding rather too readily to something new or stimulating; too easily excited.
Chip could be a bit wayward and excitable
kind, friendly, and patient.
Everyone was very good-natured about my comments.
friendly, good-natured, or easy to talk to.
He was an affable and agreeable companion.