Factorization

Several students have mentioned about being uncomfortable with "factorization." I would like those students to please tell me to what they are referring. Factoring trinomials? Factoring by grouping? Completing the square? Factoring higher order polynomials? Removing perfect factors from within radicals? Removing common factors from expressions? Finding the greatest common factor of two or more terms?

Be specific; consider giving an example or two.