Apparently it is today. Also, today is national cake decorating day, but I am going to skip that one. 
Just out of curiosity - what are you carrying if you use handbags? I will start. I am heading off to work with my trusted Kate Spade tote in “cats and cream” with wallet on a chain tucked inside. When they fall apart, they will be replaced with something that I will carry until it falls apart. Not a multiple purse person.
I have a Clark’s nylon bag with 3 zippered compartments on the outside as well as a magnetic closure on the opposite side and two large zipper compartments on the inside. It’s perfect for travel as it helps keep my stuff organized. It’s black as are most of my handbags.
A Chelsea hobo from Coach. Zip top, both long and short straps. Most of the time I wear it cross body. Same as BB, not a multiple bag person. This one is big enough for wallet, planner, other miscellany, has interior pockets, is flat enough to not sideswipe my fellow pedestrians on city streets. And black. Always.
My other favorite bag is for longer rambles with my dog. It’s a regular Timbuk2 handbag and has room for water bottles and waste bags, collapsible dish, side compartment for kibble and treats. Long strap for cross body use as well. I formerly used a backpack but didn’t like having to remove it to give my girl a water break. Again, in black.
Every bag I get has to have a small, immediately accessible compartment for an allergic reaction info card I carry. Three of my family members have life-threatening food allergies, so I made up a bunch of these cards and have one in every bag in the easiest spot to reach. Keys are way down the food chain in comparison.
I remember my mom changing bags to match her outfits as I was growing up. Does anyone do that any more? Or, maybe it was only my mom that did it even then!
I rarely change purses for most outfits tho sometimes will use a smaller, lighter bag for evenings out than my regular cross-body bag. My mom only has 2 black purses that she puts all kinds of stuff in.
One of my friends has always coordinated purse with outfit. Another friend coordinates purse with season.
My every day bag right now is a Rebecca Minkoff black satchel that I’ve had for two years. I might get a new bag this season but haven’t gone out of my way to shop for one. I also need a new black envelope for evening.
Handheld black leather boston bag discreeetly stamped with my own initials, with a bright red organizer inside so I find my black wallet and eyeglass case more easily. Since the lining is also black, that was a problem for me before the organizer. This has been my daily bag for the last 18 months. It is not perfect, but it’s the best for my needs so far. I would prefer to carry a smaller bag, but it has to hold sunglasses and a kindle and a phone. At that point, it is not a small bag any longer.
Handbags are a challenge for me. I keep trying to do what you do, BB, but it just won’t work for me because I can’t find a tiny crossbody that will hold my eyeglass case, no matter how small a wallet I use. And since I live someplace very sunny, I always have my prescription sunglasses on outside and change them when I go inside. And I do a whole lot of walking from one place to another with friends. An open tote doesn’t work for me since it will inevitably spill all over my car or the sidewalk. And if I put everything in it in containers, it gets heavy and difficult to access.
I have a few exquisite small handheld bags I carry at night sometimes, when sunglasses aren’t necessary. But I really don’t like to change things out of one bag into another because it tends to confuse me where everything is at any particular moment. Some of my small bags belonged to my mother or grandmothers. I am old enough to remember matching my bag to my shoes.
BB- can you fit sunglasses and/or a phone in your WOC?
My mother had matching shoes and bags! I am still constitutionally unable to wear a bag of a different color than my shoes. So, yes, my shoes are all black too.
When our boys were very young, my father had a mild medical episode in church and was taken to the ER. My mother called us and DH met them at the hospital. He says when he walked in, “Most of the people in the waiting room were in casual clothes, sweats, whatever they threw on to get out the door. And there’s your mom, perched on a chair in her skirt suit, wearing pumps. Her pocketbook matched her shoes . . . and had a little matching leather FLOWER!!!” He thought it was amazing and endearing.
@alh - yes on the phone, no on the sunglasses. I suppose a very flat pair of readers will fit in, but that’s it.
My current everyday is a blush Kate Spade crossbody. Will be switching to black shortly. I do admit to matching my bag to my shoes/outfit when I go out.
Most of my footwear is black as are most of my handbags, so they generally match. 
I was doing errands yesterday with a very simple, very small Fossil cross body purse, in black. I have two other Fossil purses, larger, that I like a lot. One brown. One black. Zzzzz…right?
All from eBay because I cannot bring myself to pay retail!
My current bag is something my mom gave me, no identifying marks or labels. No clue what it is. Like @BunsenBurner, I’ll use it until it falls apart (my MO from cars to underwear). What’s the point of National Handbag Day? Or Cake Decorating Day? Just silly.
My current bag is a Marc Jacobs hobo in a light brown, butter soft leather with silver accents. I love the size of the bag and the color.
I am carrying a convertible crossbody/backpack purse that I purchased in Canada from a small Ontario based company. Not tiny, not large - JUST right. It’s a beautiful grass green color - maybe slightly darker. Good pocket storage and zips shut with brass features. I love it and while I sometimes will change to a “winter” purse don’t know that I will this year. I don’t play the matchy/matchy game for daily use!
https://building–block.com/products/178
I have been considering this idea for holding sunglasses and a wallet for a while now. (There must be much less expensive versions around). The pieces could be worn crossbody or go in a tote.
It would not be as elegant as WOC, but maybe more practical for me.
BB: I do like your tote/WOC concept a whole lot… My ideal.
Cute concept of that building block, but I will find the constant banging of the blocks against each other annoying. I walk very fast! 
I park my tote under the desk, and if I need to run out, grab the woc. Or sometimes I even pull a credit card and shove it into a slot on my phone cover. Kind of like this:
http://m.shop.nordstrom.com/s/kate-spade-new-york-leather-iphone-7-8-7-8-plus-folio-case/4715963
Kate Spade Cobalt Blue tote. Everything fits inside. I have a lighter weight softer blush tote that I have used on weekends this summer. I’m looking for a new bag as well but I’m hoping I just stumble across it. Magically. And on sale.
Because the weather has continued to be so hot, I am still using my summer yellow Coach bag… but soon will be swtiching to my amazing dark brown Coach hobo bagor maybe a dark blue one. I also have a small black Coach bag that I use for going out at night that I can just throw my phone, my license, my keys, small brush, lipstick and blush into. I am a fan of Coach… as long as is classic Coach, not the dreadful look that they had for a few years with giant logos all over. .
I spotted quite a few fake GG-print Gucci bags on the bus today…