What do you think about the ternary operator?

A single ternary is fine, as long as you don't write down a long line of complicated logic. It's especially joy when providing default values for variables that may or may not have a value.

Screw multi-ternaries though. Even when aligned properly I hate reading those and figuring out what they do exactly.

for me, ternary operator is only good for one expression only.

I like them quite a bit. Like everyone else has said, they're pretty easy to abuse or sneak into a place they don't belong.

I love to use them, a way for me to avoid "If ... else" statement when I want to do one-liner

Absolutely love it for it's simplicity and how widely it's been implemented in almost every programming language.

But I absolutely cannot stand it when someone does something like this:

return expressionThatReturnsBoolean() ? true : false;

or this:

return !expressionThatReturnsBoolean() ? true : false;

or any variation of taking an expression that returns a boolean and immediately transforming that boolean with a ternary operator to return a boolean.

I've had many people tell me that this improves the "readability" of the statement, but I strongly disagree. I think all it does is add redundancy to the code and add more complexity with little benefit.

every time someone uses an else instead of a ternary a cute cat dies somewhere.

Everything can be written in multiple different ways. The Best Way™ to write something depends on what it is you're trying to write. Sometimes it's much more readable to write a ternary expression, and sometimes it's much more readable to write that same code in an if, and sometimes in a switch, and sometimes using a dictionary or whatever other idiom your language of choice offers. The important thing is to (re-)write code in the most readable way whenever you touch it. There are no hard and fast rules. A piece of code may start out as a ternary expression, but when added to must be rewritten into something else to remain readable. Things become unreadable when you leave something as is (e.g. as a ternary expression) while adding to it because you don't feel like rewriting it.

I think languages need it. I think it's necessary for making the code flow in the same order as how things work in your mind. But I don't think it improves readability except in Lisp (because it's just a regular If statement).

In Lisp (It's been a few years, so forgive me any syntax errors) it's:

(setq variable (if condition something somethingElse))

In Python what it actually is is:

variable = something if condition else somethingElse

Whereas I'd like it to be:

variable = if condition something else somethingElse

I tend to use the conditional operator mostly with one-line functions or properties. The idiomatic syntax is a lot easier in C# (my most used language) for one-line functions using the conditional operator.

New Hotness:

int Max(int a, int b) => a > b ? a : b;

Old and Busted:

int Max(int a, int b) {
    if (a > b) {
        return a;
    }
    return b;
}

It's like an if-else in Scala, that returns a value. Nothing wrong with that, it's just that ? : is not intuitive to read. But if used carefully, and not just showing off how smart you are ;-) it can actually improve readability.