Stress
There's a definite degree of stress in striving to arrive at a beneficial conclusion with respect to your research, but, assuming you went into the field that grabbed your attention the most, the work is interesting and your daily routine varied. Hopefully you're not a huge fan of monotony. (We call dibs on the wheelbarrow.)
The corporation or agency you work for is going to want answers to their questions, though. They're not paying you just to have you come back to them and say something like, "My research produced no viable results. Sorry." You may not be measuring chemicals in test tubes, but this is a science, and science is result-oriented. So if your research produces no viable results...you'd better make something up.
No, wait. Don't make stuff up. That'd be unethical. Forget we mentioned it. Just go back there and try harder.