Sometimes when using pacman -Syu it leads to conflicts.
Depending on the conflicting files it's either easy or hard to tell which package is causing problems.
So it would be cool if pacman would tell which package is causing problems instead of just telling the conflicting files. So I wouldn't need to find the right package myself.
to check, what pkg owns a file, you can use
pacman -Qo /path/to/the/file
The impossible missions are the only ones which succeed.
...and sometimes files are not owned by any package. Also for a user it's usually enough to check only one file for a package that owns it. This is a slow process and pacman would be forced to check every file - this potentialy would lead to a looooooooooong brake in your work :-)