Was I lifting a 6-liter Wilkins bottle? I thought not but it was really Wilkins. I had the feeling it was lighter. Hmm. Do you know what made me think it was not?
All 6-liter mineral / drinking water in PET packaging come with a feature similar to handbag. Any buying customer can carry it on the spot without putting it in another container, a sando bag, hand bag, bayong or similar. If the feature never exist then the normal thing to do is to place it in carrying bag, grip it underarm or hug it with both arms.
However, an average human can carry it only for a relatively short distance. The weight together with the narrow handle tend to strain the hand easily. Buyers taking a long walk are gripping it underarm, hugging it with both hand or placing it on shoulder. The manufacturer realized this and made the bottle handle twice as wide for customer convenience.
Given a constant weight, the one with wider handle feels lighter and more comfortable to carry.
I think making it wider, about one inch, and rounder is a nice step.