You don’t actually need to dirty a bowl— you can mash it with a fork and mix it right on the cutting board.
You don’t need to even to dirty a cutting board. If you are careful, you can mash it gently in the skin with the edge of a spoon, then scoop it out with said spoon.
I use a paper towel. 
When this boomer was in high school, we had over a dozen avocado trees in the yard. We skipped the toast and spooned them right out of the rind.
Dad would take sacks of them to work and sell them for half what they sold for in grocery stores. Black-market avocadoes!
Yeah, avocados, along with citrus, was something people brought into work from their yards. I never actually bought a lemon until I was well into my 30s.
I’m about a month, month and a half from the influx of fresh from my MiL’s garden tomato glut. And I look forward to having a slab of fresh tomato, chunk of avocado, and minor slab of mozzarella sprinkled with coarse smoked salt and fresh cracked pepper on sliced baguette, with just a squeeze of lemon to top it all.
It may or may not qualify as “avocado toast” but I’ll be enjoying it, although not putting it up on social media.
[ note, although after 2-3 weeks or so, the glut of tomatoes will move onto other options of course. You CAN have too much of a good thing! ]
I’m so pleased that people have finally discovered the joys of avocado toast. Nothing new about it. My grandparents had avocado groves in California way before WWII and mashed avocado on a piece of toast was a common addition to breakfast. I’ve enjoyed it–and plain old avocados almost since birth (and that was a long time ago). Mash up an avocado, add salt and pepper and apply to buttered toast. Heaven.
Through the years I have mentioned this dish to various people and have always been met with a reply along the lines of “…so…interesting.” So now I’m glad that people have discovered the joys of eating what was a nice breakfast item to my family.
My maternal grandmother lived in Anaheim, and had a large avocado tree behind the house. We’d come home with a grocery bag of avocados when I was little. 
Tomatoes no, but bananas absolutely (the local Hawaiian ones, not those hideous Cavendish from Chiquita that most mainland Americans mistakenly think of as “bananas,” though I’m sure you could refrigerate those too).
Sometimes you just can’t eat all the bananas or avocados before they rot, if they are left on the counter. Refrigeration slows the mushification process down to a level where a human appetite may be able to keep up, if the produce infestation is not too out of control.
I suppose in a pinch one could refrigerate tomatoes too, but I don’t seem to have a problem with excess in that particular case.
And you can store bananas in the fridge. The peels blacken, but the fruit is fine.
I don’t like what refrigeration does to tomatoes, either.
As long as we’re discussing whether or not refrigeration is appropriate, does anyone refrigerate their peanut butter? As a New Englander I thought that was totally weird but my Florida and Hawai’i friends all did. They told me there was some toxic mold that grows on PB in warm climates if you don’t refrigerate.
So I dutifully refrigerated PB once I moved to the tropics, until I read that while there is indeed some kind of toxic peanut mold in the world, you don’t have to worry about it on peanut butter and refrigeration is unnecessary.
I stopped refrigerating my PB then. That was years ago, all spent living in hot places, and as far as I know I haven’t killed anyone by serving them unrefrigerated peanut butter.
I’ve never had an issue with refrigerating ripe tomatoes. I generally don’t, as I eat them fast enough, but if I won’t get to them, they refrigerate fine for me with no noticeable loss of flavor or texture. You want to refrigerate them when they’re ripe, though. Underripe and that’s when you run into problems.
Relevant article in the New Yorker
Many interesting points in it.