Matthew 13:3-23 is the Parable of the Sower. In that parable a farmer throws seed onto pieces of land that would never produce a harvest. He threw it on a path, a rocky place, among thorns, and also on good soil. In each instance, except on the good soil, the seed did not produce what it was meant to. We can read this parable and miss a key point: Though most of the objects the seeds landed on did not produce; the objective was that the seed was thrown onto them regardless.
A wise and conservative farmer would never throw seed onto soil that would never produce a crop. However, a reckless farmer would. A reckless farmer would throw out seed unconditionally.
In sharing our faith we can become too wise and conservative to the point that if we feel that the seed of the gospel won't be produced in a persons life we don't bother throwing out the seed. That is never the point of the gospel. We don't pick and choose who God reaches.
We need to be like the reckless farmer who throws out the seed undaunted by where it may fall and what may happen. The reckless farmer loses a lot of energy throwing the seed everywhere but God will bless his harvest.