Arrogant, Pompous. A Braggart
a person who is always in a good mood is called jolly, or enthusiastic
The preposition for the word "boast" is "about" or "of." For example, you can boast about your achievements or boast of your accomplishments.
A person who always thinks the worst will happen is known as a pessimist.
person always wants to win
A person who always expects good things to happen is called an "optimist" A person who always expects bad things to happen is called a "pessimist".
Family/Best Friend
Incessant complainer
A hypochondriac
boast
My friend Nathan.
A person who is always learning new things is often referred to as a lifelong learner.