Sometimes I'll sit by a waterfall and just watch the water cascade down, minute after minute, in what seems to be an endless flow. How, I marvel, can rivers flow, and flow, and flow, and not run out? Water is one of the world's greatest treasures.
Thoughtful is an interesting word because it can mean someone who thinks a lot, and because of that isn't easily manipulated, and also someone who thinks about others a lot, acting with corresponding compassion and understanding.