A person's response to being burglarized is never purely rational. You've got the distress of the initial discovery, followed by the subsequent process of figuring out what (if anything) they stole, modified, or left behind, and the process of reporting the crime to authorities. Then you'll deal with self-blame about not investing more in home security and uncertainty about whether these thieves will come back for what they left behind (did they break in knowing you were gone, or did they mistakenly think you were home...?). Even if you had excellent video surveillance coverage that proved that they only took stuff you'd forgotten about, the burglar(s) violated your personal space, which obviously feels pretty awful, and may have broken something on their way in. The negativity of getting burglarized is irrational in nature and difficult to quantify in economic terms, but is nevertheless real.

In conclusion, I'd say every victim of B&E has great reasons to be upset, regardless of what (if anything) was stolen.