Variation; positive or negative?
Variation is positive in contexts like "Varied workday," "varied training", "varied lives", etc. For manufacturing companies variation can create headaches and huge cost. Variation of process parameters can cause the product quality to vary more than desired, resulting in customer complaints and quality costs.
All processes are subject to variation. Some might protest, but if you go into depth of things, you will always find differences. Two "identical" houses will be different if you study them more closely; nails are placed differently, the wood will be slightly different and have branches in different locations, etc. Even identical twins will be a little different when you become familiar enough with them.
In the "old days", there were many creative explanations of natural variation; if one failed to churn butter, someone was in love. The Norwegian Fishermen have a funny explanation for poor fish catches; bad "Haill". You have to ask them what it means; I am not going to explain it here...
Some processes have little variation, while others have greater natural variation. For manufacturing companies, the finished product may vary depending on the conditions during the manufacturing process such as temperature, pressure, time, pH, amounts, etc. These conditions will vary, thus providing variation also in the final product. Six Sigma uses a tool called "Components of Variation" - CoV, which can be used to identify sources of variation and quantify how much each factor contribute to the total variation. This tool has many applications. I have used it to assess variations in my own weight. You can watch the video with this variation example.