A good airplane will fly from Mexico to San Francisco, coming to rest at the airline terminal. A bad airplane will experience control problems, coming to rest in pieces at the bottom of the Pacific Ocean. Sometimes 'doing what you want it to do' means the same thing as 'idiot proof'. Good technology minimizes the possibility of unexpected consequences by minimizing the potential for operator error. Good technology will also be robust, less prone to breakdowns and malfunctions.
Reliability seems like an obvious point but is frequently overlooked in less critical environments.
Software which crashes instead of running is obviously bad technology. Telephone systems which connect you to India instead of Indiana are not useful. Doing 'what you want it to do' is a highly personal thing. Parents often criticize teens' clothes because they represent bad technology. If you want clothes to protect you from the cold, then your daughter's selection of light chiffon and an ultra-mini represents bad technology.