Answers: (based on own opinion)
1. I would rather think about the positivity in life than thinking or maybe doing self destructive things.
2. I would deal on foolishness by thinking clearly or sorting things out by means of sorting myself out than being fooled by people, myself, etc.
3. Dealing with lack of contentment is hard when you can't even be content with only one thing. But we should always be grateful for what we are, and what we have.
4. Aggressiveness, A lot of people or even myself (yourself) can be aggressive sometimes, and it's not a big deal unless you are putting others down for your own contentment or doing something with so much unnecessary aggressiveness. Which we can deal by being calm at times.
5. Try to look on another perspective or the perspective of the people you are being 'hard headed' on. Also, I try to understand things / or maybe sort things out, everything can be talked out.