That's absolutely rediculous.
Theres nothing wrong with wanting to strive for more in your life. You don't have to be content all the time; thats what creates improvement
Happy doesn't necessarily mean satisfied, I'm happy, and I want/strive for things.
Being unhappy however is (usually) just mismanagement of emotions in teenagers. Of course there are exceptions like if you lost a loved one, but I bet all the people who voted no are just angsty teenagers.