The most powerful paintings can speak quietly.
They must be subtle enough that you want to live with them for years- drinking in what you can when you can or ignoring them when you must turn to other things. If paintings came on with all the clamour of a rock star they might gather crowds quickly but over time the crowds would drift away.
Instead the best paintings call for your attention quietly. Heck, they only whisper. Yet their power plays out into your life for a long, long time.
The point of art is to make something rich enough that each time people come back to it they discover something new. There are Rembrandts like that I've been looking at for decades. He'll make tiny things that charm me, like the how one finger is painted with sharp staccato strokes while the adjoining fingers are softly smudged. It's been done so well you feel he's painted it exactly the way it had to be. Somehow Rembrandt has won us over into having an almost timeless relationship with him. That's real power.
My neighbor has a ridiculously shy cat named Bobo. He likes to come and take naps on the deck just outside my studio. If you speak to him in a loud voice he freaks out and bolts. To win him over you need to be artful, like a great painting. Softly call his name. Walk up to him slowly. Let him sniff your hand for a full minute. Whisper to him like a great painting and Bobo will befriend you.
When I painted my oil The Song of All Days above I knew I wanted a super high contrast of prickly vertical pines against a wide open light horizon. You have to get the viewers attention. But what keeps me wanting to go back and look again are the little things. Like the soft gradations in the butterscotch colored sea in the lower right corner.