I see that the Boston Common (NOT "Commons"!) is the #20 attraction in Boston, and I'm wondering WHY?!
It's a park. Compared to Central Park, it's a postage stamp. It houses homeless people who sleep on the grass and benches. It's historic, big deal. There's not a clod of dirt or cement sidewalk in Boston that ISN'T. It does have the Frog Pond, which is not a pond and has no frogs. In summer it's a wading pool with a sprinkler; in winter it's an ice skating drink. And one week every summer the Commonwealth Shakespeare Co. (Shout-out!) performs for free. That's IT.
Do yourself a favor--cross the street to the Public Gardens. Wander through the beautiful flowers and take a slow ride to nowhere on a Swan Boat. Then stroll down Newbury St. and look into all the eclectic shops.