What's the reason of keeping the chairs opposite to that of the mirror? By keeping this, the person whose hair is being cut has no idea about his haircut. He can't suggest any modification as well till he looks at it in the mirror!

You could ask the barber... I expect there are two major factors. 1) Most people are staring at the TV anyway. 2) Seeing your haircut in-progress isn't going to tell you anything, and you might be prone to ask them to change what they're doing in the middle of it which is probably a recipe for disaster.

After reading Brian's response, I went ahead and requested the barber to turn my chair towards the mirror. She politely refused :) She told that the clippers, trimmers, the pairs of scissors & other stuff that were on the table would be far away from her if I faced the mirror and she behind me. 😀

Most clients want to watch the t.v. I bet if you told them you aren't interested in watching it and could they turn the chair around they would.

Element of surprise, perhaps... 😊