Am I overreacting??

So a little background my boyfriend and I have been together 7 months but have known each other about 7 years so we know each other pretty well. We are pretty serious we adopted animals together we vacation together we talk about marriage all the time I truly think he’s the one. HOWEVER he has a tendency to freak out and have little meltdowns and I don’t think it’s a deal breaker so no one tell me to break up with him because that is not the question, he is literally perfect 98% of the time. but how can I get him to see that he needs to change some of his behavior- at least around me?

I have to be clear he doesn’t freak out as in hes abusive or anything like that he treats me like a literal princess and I think maybe has raised his voice at me one time if that. I’m talking about like stupid slow people in line at the grocery store he will literally say SUPER LOUD like shit about themso they can hear. Or his coworker who is our roommate like he is so rude to him about him being lazy which yes he is lazy but instead of talking to him in an understanding way he will literally be passive aggressive and slam dishes and be hella loud like “I love doing other peoples dishes it’s fucking awesome.” Like I get it things annoy you but I am so go with the flow chill person like things annoy me but I don’t let it get to me. Like I hate awkward situations and unnecessary confrontation and I have anxiety so I like to have peace any chance I can get.

Well today we got in a huge argument because I had just worked all day, and I have a hurt shoulder right now so after work I just wanted to go home because I was in pain but we had to go look at a box spring and mattresses and I really wanted to get it over with because it’s our only day to do it. Well of course after he picks me up we are driving and some douche in a huge lifted truck cuts him off and I see him instantly getting heated and I’m just like babe don’t I’m not in the mood just let it go I’m trying to look up this mattress place and I don’t feel good and he doesn’t listen he’s already speeding up to this car that cut us off and rolls down the window yells at them flips them off the whole deal, and I about had it. I told him take me home I don’t want to shop with you I can’t handle this stress like we aren’t getting the damn box spring that we only have today to get. And this started a huge argument about him saying I knew who I started dating from the beginning and I’ve known him for years and knew this is how he was and that he shouldn’t have to apologize for freaking out on a stranger and that I should have his back and that it has nothing to do with me and I had no right to get mad. Am I overreacting?? Like I’m sorry but I’m a total advocate of not changing people in relationships, and In some ways I like that he calls people out and doesn’t take shit from people but there is a line and if I’m not comfortable getting in road rage altercations among other things shouldn’t he respect that?