Why are people so mean?

I'm trying really hard to structure my new normal. I'm putting myself first a little more, I'm saying yes to lots of things I wouldn't have done before, I'm trying to give back, and I'm doing nice things for myself because life's too short not to, right? One of these things is to buy myself fresh flowers every week. Nothing too expensive mind, no more than $12. I've denied myself this pleasure for all 19 years of my married life because you know, frivolous expense. But I drink way less alcohol and coffee now, which saves a bit of money, so I don't feel as guilty. 

So today I was at the chemist in my local shopping strip, filling three prescriptions (that'll be $63 thanks...) and there was a 10 - 15 minute wait. I'll go and get my flowers I decided.

I went down to one of the two greengrocers because they sell flowers that aren't too pricey. I settled on a bunch of very pretty pale pink orchids. There was no price label so I asked the owner. $7. Ooh, maybe I can get two, so I said pleasantly, would you do two for $10? I can do two for $14 he says. I smiled, thought, oh well, one it is, put the other one back and joined the queue to pay.

Then I notice the florist down the street was still open and decide to head down there to see what they've got. Well they had nothing decent so back up to the greengrocer to get the orchids.

I arrive to see him putting the bucket they're in out the back. There's no one else in the shop.

"Sorry they're gone. You can't have them" he says.

Me, smiling, "They're just out the back, surely you can just get me one"

"The pink ones are gone. You can't have them"

Still smiling and attempting jovial, "No they're not. I just saw you take them out the back"

"They're all sold. Someone has just bought them all"

"No they haven't. They're out the back. Why won't you give them to me?"

"You can't have them"

It went on like this a bit longer until I said, getting upset, "Why? Why are you doing this?"

"You can't have them"

Getting really upset now, "Why are you being so mean?"

"You can't have them. You'll have to go somewhere else"

"Why are you being like this? Do you know why I want them?? Why are you doing this to me?"

And then I started to cry. I'd had a really nice day for a change and this ARSEHOLE was being VILE. He was so obdurate and unpleasant. I felt so hurt. I said something about not understanding why he was being so horrible, and then finally he went out the back to get the flowers.

And while he was gone I got really angry. Why was I letting this prick treat me like this? And I was going to reward him with my business?? Like fuck I was. So when he came back, through my hurt and furious tears, I said, "You know what? Forget about it. I've got cancer (yes I went there, slight blurring of the time line but fuck him) and I just wanted some flowers to cheer me up. I've shopped here for 18 years and I will never shop here again. You're an absolute bastard." And I ran out into the street, sobbing, and stood a little way up the road with my face in my hands.

And then I stomped up the road to the IGA and bought a beautiful bunch of little pink tulips for $8.99, got my pills and went home, shaken and miserable.

Any halfway decent mood I have is so fragile these days, the slightest thing can shatter it, and ever since this incident I've been so sad. Why do I even try? Why are people so mean?