Do I say "people like me who is happy all the time" or "people like me who are happy all the time"? Is it is or are?
Seems like it should be are as people are plural.
"People" is a singular noun in its form, and it has a plural form. But the form is ignored syntactically because the meaning refers to more than one person, in most cases, many more than one person. So "people" is treated as a plural noun despite its form. This is NOT true of many nouns that, in the singular, refer to multiple persons or objects.
EDIT: So you are correct: you say "people are."