Simply put: Complainers hardly pray. Those who pray hard, hardly complain!
Which one describes you?
Are you filled with disgust, upsets, anger, discouragement, fear, envy, jealousy, and the like? Can you honestly say you adore and worship the Lord EVERY DAY and spend at least one hour in prayer daily? I kind of feel if you answered the first question, "yes", you probably answered the second question, "no."
On the other hand, are you finding witnessing (even a simple "God bless you") is rather easy to do? Are you finding God's peace flooding your heart; your love for the Lord is deepening; you seek to encourage those in ministry with kind support and a LOT of prayer support? If all of that is true, do you find yourself complaining a lot; getting discouraged a lot; can't remember the last time you gave a word of witness to someone? Again, I think if you answered the first two questions with a "Yes!" you very likely answered the last question with a resounding "NO!"
Christian, like our Daily Verse warns, if you spend your life complaining you're right in the "cross-hairs" of Satan's darts! On the other hand, if you're spending quality time with the Lord in prayer, worshipping Him and then pleading with Him on behalf of others, you'll find Satan "heading for the hills!"
Don't let Satan trip you up. Send him packing! PRAY and PRAY HARD! I will hardly have to say, "Complain less."