if I may elaborate on "everything is an expression," F# allows you to do things like (with apologies for being a tad rusty with the syntax)

  let bar = 
      if foo then  
         7  
      else  
         11

  let bar = 
      try
        // code that might throw
        7
      with ex ->
        11

Whereas in C# you have to do like

  int bar;

  if (foo) {
     bar = 7;
  } else {
     bar = 11;
  }

Except that most C# developers do

  int bar = 0; // or some other default value`

This doesn't seem like a big deal given these examples. But it becomes a much bigger deal when the if/else grows super large, becomes nested, etc.

Also C#:

bar = foo switch

{

   true => 7,

   false => 11

}