Not really a "dumb thing", but a suggestion nonetheless. I think it would be great if instead of saying the app name to Cortana when we have her perform a certain task, there should be a list of default apps to which she would automatically launch if a certain comand is heard. For example,
No
Me: Fourquare, show me good restaurants in the area.
Yes
Me: Show me good restaurants in the area.
Cortana: Okay. Which app would you want me to open?
Me: Foursquare (assuming you also have Open Table installed).
Cortana: Do you want me to open this app by default?
Me: Yes.
Cortana: Okay.
This makes Cortana more natural and human and less like the pre-modern voice controls of WP7 and equivalent OSes.
I already made this suggestion to Cortana via its feedback; I would appreciate it if everyone who likes this idea does so as well. Maybe it could be implemented in Windows 10!