The next time you get rejected for the Gospel's sake or someone takes your tract and throws it in the trash or you get yelled at--be like a bee. A bee doesn’t sting the flower when it doesn't have pollen, it just moves on to the next flower to see if it can find pollen there.
So when you have a "bad" witnessing encounter, take courage friend and don’t get upset and “sting” the individual. Just move on to the next person. Remember not to take it personal. It's the message they are rejecting. I'm comforted by Jesus' words that are for the Christian, “Blessed are you when they revile and persecute you, and say all kinds of evil against you falsely for My sake. Rejoice and be exceedingly glad, for great is your reward in heaven, for so they persecuted the prophets who were before you." (Matt 5: 11-12).
There's no such thing as a bad witnessing encounter.