#1 They Think They Are in Competition With You
Competing with others is not just okay; it is also normal. Although it can occasionally cause serious harm. It is true that rivalry is a healthy trait in some people, but not all of them. Your ability to control your competitiveness is the most important part and the key to a healthy type of competition.
If you have a competitive mindset, you could feel envious of the other person if they are better at something than you are or if they have something you desired but weren’t able to obtain since it was given to someone else instead of you. Everyone occasionally feels jealous, which is a common feeling.
On the other hand, if others perceive you as a threat, they could try to undermine you by tanking you behind your back in order to feel superior about their own circumstances by comparing themselves advantageously to you.