The word "pinche", according to sources is an all-purpose insult enhancer, which would be roughly equivalent to the use of the F-word in English.
It is strongly associated with cursing which is not just isolated in Mexico. Reports say that people from Panama and Columbia also understand that it is used to describe something insignificant.
While "mayate" references to a black dung beetle and a derogatory term used to describe a dark skinned person.
Combining these two words then will give a very clear explanation of what they imply to.
The words you use are more powerful than you imagine. Most people greet each other with words that have no power.
Learn these 10 Simple Word Swaps to get the best from yourself and others.