The Shikker Dovid read a beautiful thought from a holy website known as www.emunadaily.com. He encourages all people to read it. The thought is taken from Mishlei “One who guards his mouth and tongue, guards his soul from troubles”
In Behaloscha, Bnei Yisrael ‘murmur” against Gd. Despite having the food they need provided, the cloud of the Holy One to lead them. They still complained. Was it from lack of food they complained? Certainly not. The Shikker Dovid opines that they complained because they were not happy or content with themselves. They were not comfortable or secure in themselves. They needed to feel better about whatever insecurity they had by complaining.
Our souls and mental health would be better when we hold our tongues and do not speak bad about others-but also ourselves, our surroundings or our circumstances.