School uniforms instil a sense of discipline into the school day. They are an efficient eliminator of choice. A school uniform is a vital part of respecting one's school and the start of a more disciplined approach to learning.
Clothing is the outward signifier of respect: those in power require these to make a clear distinction between those with power who have value and those who have neither. As a society, we are reaping serious social damage due to our lack of respect for our children.
What is the point of exams? I mean, HOW do they help you in later life? Can't you just, not do any until you're like...I don't know, in uni? That way, you can enjoy your teenage years while you still have them!