I love to walk: in new cities, my cities, open fields, pretty much anywhere is good place for a stroll. But Amsterdam leads cities not only for walk-ability but for things to see. I have yet to find a boring part of Amsterdam and I've spent over six months of combined time there.
One pleasant walk is through the floating flower market or Bloemenmarkt. It is not far from other sites, there's food vendors in and near the markt and there's some of the best shops for silly souvenirs you could ever wish to find.
The floating flower market is made up of moored barges brimming with tulip bulbs of every variety. Note some are specially marked and will clear U.S. customs, while others will not. I presume it's less strict within the EU. There's tons of bulbs, cut flowers, and tulip paraphernalia - yes, that is a thing - available for purchase and often at rather good prices. Along the street are several cafes serving a mix of Americana/British breakfast foods, sandwiches, and beverages and while the food is not that exciting these places have front row seats for people watching.
Tulips are hugely iconic in Amsterdam and the Netherlands and it's only proper to appreciate the rich variety of the flower that inspired the first market crash in history!