Object Complement vs. Infinitive with actor ?

"I want him to go"
I know that "him" is the actor of the infinitive and "to go" is the direct object.

However, somewhere on the internet, I came across this sentence.
"I made the dog really happy"
I always thought that the "(to be)really happy" was the direct object answering "what" was created, the happy feeling. But the website said that "the dog" is the direct object and happy is the object complement. Why?

What about these sentences?

"You make me feel happy"
"She made them her assistants"

Oh and on another note,
"This was a bad decision for him"
"for him" does that modify the noun decision, or adj. "bad" (answering why it was bad).