One argument one reads in the press against eliminating waste from team members' cycles is that waiting time is resting time. They argue that if a person has to walk across the shop to find a missing tool, they are taking a leisurely walk, relaxing those cramped muscles. If a person's work grind to a halt during a work cycle, they can take a breather from work.
Isn't this like saying that one you're in the garage and realize you've forgotten your car keys, you can take a relaxing walk back to your place to get them? Or that when you're waiting for the bus you can enjoy a breather from the manic pace of your life. Or stuck in traffic is a good time to relax from the burdens of keeping a several-tons metal machine on the road at high speed.
I've always found this argument profoundly disrespectful. For one thing, I believe team members care about their work and want to do good parts on time because this is their fundamental contribution to society, and I having worked on shop floors for many years, I really believe this is true unless management does what it usually does to discourage the feeling of contribution. Interruptions are no more pleasant in hands-on work than in any intellectual pursuit - they's interruptions, not breaks.
Secondly, happiness psychology tells us that people feel at their best when they're in a state of flow, when they meet a slightly challenging goal with a smooth, uninterrupted cycle which takes them into a special mental zone, which is what happens to any of us playing sports. In flow conditions, time disappears and there is a contentment in doing something well.
But what I find really perverse about the "waiting is resting" argument is that it's allows management not to bother with working with team members to improve the flow and fix interruptions in their work. Similarly, by not aiming for a real target but by assuming that because people get tired during the shift they can slow down at the end, management basically opts out of solving the reasons why people get tired - where is the overburden - how are work conditions designed in a way that makes people tired.
This does not just apply to shop floor work - the verdict is in about open space office design: it's disastrous for concentrated work!
Every second of every person's life is precious. We have not yet reached a stage where all people can live the way they choose and do just about what they want, so we are all burdened with work. This is not necessarily a bad thing, as work is also a source of earned success and happiness. We all love breaks but who enjoys an interruption? Let's work together to reduce variations in the work cycle to get longer breaks and smoother, more productive jobs.