What are common pitfalls when concatenating strings in PHP?

Common pitfalls when concatenating strings in PHP include forgetting to use the concatenation operator (.), mixing up single and double quotes, and not properly escaping special characters. To avoid these issues, always use the concatenation operator to join strings, pay attention to the type of quotes used, and escape any special characters when needed.

// Incorrect way to concatenate strings
$string1 = "Hello";
$string2 = "World";
$incorrectConcatenation = $string1, $string2; // This will throw an error

// Correct way to concatenate strings
$correctConcatenation = $string1 . " " . $string2; // Output: Hello World
echo $correctConcatenation;