The two most likely reasons are a projection or a displacement. It is hard to know for sure because there are a lot of variables that could influence this, but a projection is when some internal process — often a negative one but it doesn’t have to be — is projected on to someone or something outside of us and we respond to them in a way that reflects the emotion inside.
In displacement, the negative emotion gets put out onto something or someone that isn’t the cause of the emotion but instead become a target. A parent who has a difficult day at work who comes home and yells at their child is an example of this.
These are just guesses and are not definitive at all as there are many variables that can influence these types of behaviors. If it persists you’ll want to have a chat with a therapist who can help you sort it through. The find help tab at the top of the page will locate someone in your area.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral