What do you make of the automobile under those criteria then?
Or radio technology?
Radio technology was a definite plus. It lessened the time communication took, and had relatively little negative impact on the environment directly. We did lose regional dialects, and a certain cultural individuality, but the common community and connections created as a result were good, as was the added entertainment potential, and communication speed. That increase in speed may have fostered national cohesiveness, and improved the accuracy and speed of information interchange, which allowed technology to improve more quickly following it.
The automobile is less certain. It may well have polluted our environment beyond recovery. If it kills us, then that will outweigh any positives it might have brought. However, if the damage isn't as bad as we think, then it was mostly positive. It allowed many of the same advantages as radio, except that it also improved transportation of materials and labor, allowing people to create large cities much more quickly than before. It also improved defense, allowing foot soldiers to reach a needed location much more rapidly than before. The downside is the decay and squaller of inner cities, as well as the potential for more destructive wars.
If you want something that was totally negative in my opinion, nuclear weapons. They only gave us a brief advantage in a single war, and now must be maintained and researched just to protect ourselves from other countries, and are completely useless, and would only be likely to bring our own deaths if they were used. The better they get, the worse off we are if they are used.