The cactus...

I know I can be as prickly as a cactus. This is because my natural defenses come up when I feel I'm in your way or misunderstood.
People prefer pretty flowers, no one gives a damn about the poor cactus. They don't know that once they get past the pins, they'll have crucial water.
The cactus and I are brothers. Not handsome but we stand there, unwavering and waiting, arms outstretched, welcoming the thirsty travelers. Maybe saving their lives.
Alas, once their needs are fulfilled, they don't look back. And they don't notice that the remaining water are tears indeed.