From a different angle:
Rabbi Twerski MD says that some people who have low self esteem will try to put themselves above others to try to raise their self esteem. Arrogant people really suffer from low self esteem.
The Messilat Yesharim says that clothing is a function of Gaavah, arrogance. If people are trying to dress up (fashionable, flashy, etc), it could mean that they are trying to cover up feelings of low self esteem; they make themselves feel better about their lot in life.