Quick and easy way to manage ratios, so I grab a shot glass for things such as Bloody Marys, Martinis, Gin & tonic, Vodka and… oh you get the point.
If I’m serving a concoction snob, I’ll measure the ingredients. Otherwise, it’s a splash of this, a splash of that, and a pinch of something over ice.
I don’t drink much at home but, when I do, I drink 18-year old single malt scotch straight or, if I have a gin martini, I fill the glass 2/3 and put exactly one cap full of vermouth in it and 3 olives. No measuring tools needed.
I don’t use a “shot glass”, but I do use a small measuring glass like this (for the first two or so, anyway…)
I remember Mary Tyler Moore on her tv show, pouring a drink for Mr. Grant. Carefully pouring a bit into a shot glass. Holding it up and squinting at it. And he grabbed the bottle of scotch and said, ‘THIS IS HOW you pour a drink’ and glugged it into a glass. 
Finicky little wimmen measure out booze in a shot glass. Everyone else, just pours a finger or so into a glass.
My go-to cocktail is a martini, and I’ve made myself enough of them that I can eyeball the right amount of vodka into the shaker cup every time, so that once I strain it into the glass and drop the twist of lemon on top, it forms a meniscus. Perfect.
And I don’t understand why it would bother the OP when people don’t measure. Does 1/2 oz of alcohol one way or the other really matter all that much?
I generally drink gin or vodka neat. Just pour it into a glass. Nothing to measure. On those rare occasions when I use a shaker and a bit of vermouth, I eyeball it and the results are generally acceptable.
Actually, a cocktail is a mixture of at least three things and at least one has alcohol. So a Manhatten, Old Fashion, Margarita, and Martini are all cocktails. A highball is a distilled liquor and a juice or soda. Baybreeze, Cape Codder, Madras Plaid, jack and coke, tangueray and tonic: all highballs.
I tended bar and I count. I can’t help it. Hell, I count when other people are pouring.
But I don’t make many cocktails these days. I don’t care for “fussy” drinks. they tend to be to sugary for my tastes.
By that definition, how is a Martini a cocktail?
Funny - this thread had me thinking that in my 30+ years of imbibing (pretty consistently and heavily), I don’t think I ever ordered a drink that was anything other than 1 booze + 1 mixer. Usually a glass of gin, or shots of vodka or other liquers. But the occasional rum and coke, 7&7, screwdriver, bloody mary, gin or vodka + whatever you’ve got…
When I was young, my mom and dad drank scotch and gin. The only measure I knew was “2 fingers.” And, depending on the day, that could express a desire that the fingers be placed horizontally or vertically! 
You left out the bitters.
:eek::eek::eek::eek::eek::eek::eek::eek::eek:
I like a dash of grapefruit bitters in my martinis.
I use a keen eye, and an unsteady hand.
Bay Breeze is at least three things. And this is the first I’ve heard of Madras Plaid, but it sounds like it would be 3 ingredients too.
I’d be curious too. I’ve had a Madras only in Fort Lauderdale. Basically a Cape Cod with a splash of orange juice. It’s quite excellent on warm nights.
This is sort of like cooking, or maybe baking a better comparison.*
There are those who measure carefully using cups and teaspoons, and two groups of those who do not:
Those who don’t really care if it is off a bit, don’t need exact consistency drink to drink, and those who are experienced enough that they can eyeball the correct measurement fairly consistently.
I use a shot glass when making for my wife who likes her drink a specific way and am more forgiving of dink to drink variations for my own sake.
*The issue being how much you can correct by taste as you go.
Well, if you’re going really old school, the early martini recipes did often call for bitters, usually orange bitters, IIRC.
Does the garnish count in terms of ingredients? Like, for me, a gin and tonic is three ingredients: gin, tonic, and some form of lime (it could be a twist; it could be a slice, but it must have lime, otherwise it is not complete and a sad simulacrum of the perfect summer drink.)
Yeah, but really old school also called for a 2:1 ratio of gin:vermouth, too.
We’ve grown past such atrocities.
Good question. At what point does a garnish turn into an ingredient? A Bloody Mary is still a Bloody Mary without a garnish, but is a martini without an olive (or a twist)? I totally agree on the gin & tonic, BTW.
I prefer my gin and tonic with cucumber and sometimes basil.
ETA: the perfect summer drink is the Negroni.