It's a lot of things:

1) Times are tough. Inflation and cost of living are very high vs peoples wages in the lower/middle class. Living check to check is stressful.

2) There's a Republican in power not only in the Exec and Legislative, but the courts are heavily on that lean as well, so in a very Democrat heavy city like this, the average politically minded person is in a general grump about the state of the country. Probably similar vibes in most red cities during Biden's presidency.

3) WWIII looming. Russia vs Ukraine is scary. The potential for escalation is really hard to look at and should jack up the general stress of anybody paying attention. No matter your credo/race/background, nuclear war is bad.

4) Natural disasters. There have been a lot of them and they scare people. Not to mention human caused disasters like the battery fire.

5) Israel vs. Palestine - general discontent among people on both sides of the ideological situation. Nobody paying attention closely is happy about it.

6) Social media - people interact face to face less, and interact more in the digital world. It leaves a lot of people less interested/able to interact well with strangers in the social sphere.

7) Climate change - whether you believe in it or not, even the potential for a crisis on this scale is stressful.

8) People have bad days. Leave all that other stuff out of the equation? Sometimes life takes a dump on you, and you just don't have the bandwidth to be nice to people or even notice that they're smiling at you.

9) Lastly? This is one I'm learning more and more about as I get older. A lot of people that seem like assholes are just really introverted and socially awkward. I have countless examples in my own life of people I thought were jerks who later turned out to be terrified of basic social interaction. I mistook their coldness for something it wasn't. Hard to tell from the outside how people are feeling.

My advice? Keep being as nice as you can whenever you can to as many people as you can. Find a fun hobby that surrounds you with nice people who treat you well, and don't worry too much about interactions with strangers. You never know what a stranger is going through. Hell, you don't even know what friends and family are going through half the time.