Suits are classy. Besides I look good in them.
How you dress tells the world how you expect to be treated. Suits tell the world you make the rules. T-shirts tell the world you're still trying to figure out what the rules are.
I love lookin' good.
I like looking like a 60s gent
I like to wear informal, its more comfortable and makes me feel better.
formal wear makes me feel stuffy
Less demanding on the Earth's resources (usually uses only cotton), and the fact that everyone should wear one (Western ideology) means that ethics on producing it is much less of an issue (considering T-shirts would more be a necessity than a fashion statement, unless if you're A&F staff, and they are easier to make than suits).