You know what? There are bacteria living in the crevices of your gums, on your tongue, and inside every corner of your mouth. Even while you are sleeping, these microorganisms in your mouth are working. As they break down natural substances like food debris in your mouth, cells, and saliva, they release volatile sulfur compounds and other byproducts. These byproducts do not have a pleasant taste or a pleasant scent.
Thus, if you do not clean your mouth well in the morning, chances are that these byproducts produced by mouth bacteria can mar the taste of the sweet food you take in and make them taste sour to you.
Coming to the meaning of the proverb, “He who doesn’t clean his mouth before breakfast always complains that the food is sour.” If you would have to clean your mouth well to get the good taste of the food; then it means you would have to position yourself well in life before you can enjoy certain good opportunities.
For example, If you are lazy in life, you would always complain that there are no jobs. If you are not well-skilled or have not learned a trade, or have not earned a certificate from formal education, you would always complain of unemployment.
