Aggressive people often push their own ideas or try to force others to follow them.

Someone who is passive, will usually not resist the efforts of others.

(An aggressive person pushes or attacks, and a passive person doesn't resist.)

(A passive person is often seen as weak, and easy to control.)

An optimistic person believes in a positive future.

optimists see a glass as half full rather than half empty.

The opposite of an optimist is a pessimist.

(A pessimist sees things with a negative light and has little hope for the future.)

(Pessimists see a glass as half empty rather than half full.)

Sensitive people are emotional and have strong feelings about things.

It's important to be careful when dealing with sensitive people, because it's easy to upset them.

Insensitive people don't seem to be aware of or care about the feelings of others.

(It's important to know how to act around extremely sensitive people.)

(He doesn’t realize when she’s upset because he’s quite insensitive to the feelings of others.)

A mean person doesn't treat other people well, or with kindness.

Mean people often enjoy making people suffer for their mistakes.

To be kind is the opposite of to be mean.

(Nobody ever asks him for help because he's mean and selfish.)

Conceited people have a very high opinion of themselves.

They often talk about how great they are, and tend to exaggerate their strength.

Modest people don't show off their strength, but are often very good at what they do.

(Modest people are often overlooked in a job interview because they fail to communicate their strengths.)

(conceited people often exaggerate their abilities and can fool people into believing them.)

aggressive    英 [əˈɡresɪv]  美 [əˈɡresɪv]     adj.好斗的;挑衅的;侵略的;富于攻击性的;气势汹汹的;声势浩大的;志在必得的

optimistic    英 [ˌɒptɪˈmɪstɪk]  美 [ˌɑːptɪˈmɪstɪk]     adj. 乐观的;抱乐观看法的