1. Your mindset of "lack"

The mindset of "Wish I had this or wish I could do this or that or whatever" is very negative. Even worse, you start to forget being grateful for what you have at the moment. Let's learn to appreciate small things in our life. 

2. "I know best" attitude

While it is good to know your forte, you should still listen to other people's opinion to give you objective view about certain things. However, those people who simply comment without thinking or hateful people, of course, can be ignored. Haters gonna hate anyway. 

3. The feeling of belonging in a group of friends

I'd been longing for a sense of belonging in a group of friends when I was younger. Although this may be an ideal situation, we actually don't really THAT many friends. We just need some people who really matters for us, those who we can refer to as "friends for life". Now, I just try to cherish those people who matters to me.