When does evolution seem to select for optima?
Obviously, we can say that controlling for neutral processes, pleiotropic selection, phylogenetic inertia, and simply what the organism is at the start of the process, we can say that evolution in a loose sense selects for optima all the time.
But I mean if you compare something like antibiotic resistance, where it is to cause and even genetically similar in contrast to the famous E. Coli. experiment where aerobic citrate digestion is really hard to do twice. The first seems to be seeking optima in a far more specific sense.
What are some other cases, preferably experimental? And why does evolution act that way?