What's more, cactus could live in the desert, too. Hence, in the most cases, cactus stands for strength, grittiness and braveness.
I bought a bottle of cactus last year, and it grows very well under my extremely "careless" careness. That is to say, cactus is the best choice for lazy people.
Other Source:
http://en.wikipedia.org/wiki/Cactus
