Honestly, if you miss this, you've not been to Hanoi at all ! The Old Quarters is where you'll find the Hanoi's Hearbeat. Wander along the clogged arterial streets of the place and you'll find that each street specialises in a special trade. Eg. There is a street that sells nothing but herbs, another sells clothes, etc. I did not shop much there but just bought few pcs of embroidery shoes bags as souvenier.