When water is actually blue, it becomes a news item. Look downwards on most areas of water, and most of what you see is the darkness at the bottom. (I’m guessing that Google Maps colours in large bodies of water with blue for clarity). Some waters bring down pale blue stuff from higher up, especially coming from glaciers that are wearing away the rock. Our local reservoirs look as dark as peat – or darker- on Google. If the water is shallow enough, you might see a colour more similar to its bed.
But when you look at a slanty angle, you see better reflections – and if the sky is blue the water might look bluer. Memories of blue waters are likely also to be memories of blue sky and fair weather.
Myself, I quite like the sea, that greyish whooshing mass in constant motion under the grey windy sky. It’s all part of God’s creation.