It's maybe not my "fondest" memory, just a few things I noticed ...
As soon as you cross the border, you will see countless dentist offices and pharmacies left and right. Many Americans cross the border to buy their medication a lot cheaper in Mexico.
Very young kids, 5 or 6 years old, selling chocolate etc late at night on the street. The parents do not send many of these kids to school. They need the little money they might make by selling everything from candy, hats, bags to food on the street. You might also see people at intersections trying to sell newspapers or those dressed in colorful costumes dancing and after their little performance going to the cars asking for a little money.
Summer is very HOT. Winter is very cold without snow.
Mexicali is friendly.
The nearest beach is San Felipe (200Km)
Border with US at Calexico Ca.
Has no mountains nor forest.
Fondest memory: Its people, The meals (i.e. Chinese food, carne asada tacos every corner, tamalitos, champurrado). The sun