hmmm well I'm depressed, but I don't know why...

And you are right in that people are not *controlled* by others, but we do live in a social world, and other people certainly do have a pretty significant influence on each other.

As for the people who don't receive positive attention, they could still be positively reinforced for their behaviour. Positive reinforcement is the addition of a stimulus in an environment that strengthens a given behaviour. It is possible for the addition of negative attention (the positive reinforcer) to generate some sort of desired consequence for the individual. Negative attention is still attention, and if negative attention is the only way an individual is able to get attention at all, that that would be reinforcing - even if its not typically a desired response.