With Soapbox, you can create user-defined session variables to be used as default values for form fields across a number of apps. If you choose to use a session variable to populate a picklist field in Soapbox, you'll need to make sure that session variable is defined using the value for the picklist field you wish to select and not the display name.
As an example, the Shipping Country and Shipping State fields on the Shop shopping cart checkout form use the two letter abbreviation for countries and states in all caps as the value for a selection.
Let's say you have two user-defined session variables created for passing individualized data for recipients of a mass email. One is shippingcountry and the other is shippingstate. For an email recipient living in Washington State, the session variables would need to be defined like this in order to populate the Default Values for the Shipping Country and Shipping State picklists: