Every once in a while I want to change the date/time of a file by just a small amount (like 1 day or few minutes difference).
In the Attributes dialog (DOpus command SetAttr) there is a button named "Now" which fills the date/time with the current date and time. It would be nice if there was a button next to the "Now" button that fills in the date/time with whatever the current file attributes are.
The Metadata Pane (or Metadata Window; same thing in a separate dialog a bit like the Attributes dialog) may be more what you're looking for if you want to make a slight adjustment to the existing timestamps.
Folder > Metadata Pane, or the top-level icon near it on the right, can open the pane. Properties > Edit Metadata, from the button-menu just left of the Help menu, can open the similar dialog.
The date/time stuff in the Attributes dialog is more suited to setting lots of dates/times on several things at once, or copying dates from one field to another. (The Metadata tools can do that as well, making the Attributes dialog slightly redundant in terms of dates. The Attributes tool can still do more in terms of the file actual attributes, when updating multiple files.)