lj: Well your weed analogy is apt.
I own the equivalent of the red clover that invades flower beds and spreads roots slowly and is hard to get rid of because it keeps popping back up. (long term challenges--REI, EGY, VTLE)
On the other hand, there is the light green clover that gets relatively high and is very easy to pull up. (KOLD, and big name oils that pop as they did on Monday, e.g. XOM).
I farm the red clover.