I once heard it said that a weed is a perfectly respectable plant that happens to be in the wrong place at the wrong time. I cannot claim to be as merciful as the Master in the parable. The weeds become the "enemy" and I do my best to pull them up! Sigh! And yes, I do manage to pull up a "good plant" once in awhile in my zeal.
The image becomes a bit stronger when one is dealing with other human beings, however. The first Christian missionaries and missionaries today (all of us baptized folks) have had and do have the experience of "difficult" people who make the task of preaching the gospel difficult. Their example can be more tempting than the discipline of the gospel. Their voices can be louder. One wise teacher once said to me that the Lord puts them there to "keep us on our toes." And, as the parable suggests, one may do more damage trying to eliminate those weeds than by leaving them alone. Truth be told, the weeds sometimes resemble the rest of the crop too much or might be a colorful if inconvenient item, like a zinnia among the basil plants.
The Lord's advice in the parable is a challenge to the missionary. The virtues of patience and creative encounter become the goal of prayer in this case, along with the inspiring presence of the Holy Spirit. AMEN