When two expressions are strictly equal, everything including the blanks and case (when the expressions are characters) is exactly the same.
'WORD' = word /* returns 1 */
'word ' \== word /* returns 1 */
'word' == 'word' /* returns 1 */
4e2 \== 400 /* returns 1 */
4e2 \= 100 /* returns 1 */