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.
One suggestion would be undiscerning, which if taken in a perjorative sense can mean someone who is lacking in taste.
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.