The other day, I tuned by ear, playing an E major chord. I double checked with Cleartune afterwards – basically all the strings were in tune relative to each other, within a few cents, but the G string was flat, by between 10 and 15 cents. I realized it was because I had tuned a G# on that string to be a major third above E and I had intuitively tuned to a just major third. First time I’d ever consciously experienced just intonation as intuitive/natural in that way.