...because the shape of the water bottle isn't uniform either. Part of my new year's resolution is to drink 4 liters of water per day, so I spend a lot of time looking at those lines. Edit: 4 liters is a lot, but appropriate for my size and activity level. Without conscious consideration I don't drink enough water. It looks blue because the bottle is blue.
drink more water
This worked for me! They usually say you need to drink 2 liters. I tried. After 2 day's I look back ... 1 liter/day and I give up. Until I read an article saying I just need to drink more water (but within limits).
Day 1: I drank one glass .. mission accomplished !! Day 2: I drank almost 2 glasses .. mission accomplished !!
So I got myself drinking a couple of glasses ( 1..4) a day. Along with coffee and tea etc ... I think it's enough, I'll live