Acne. While it is disappointing to have acne after the teen years, it is not uncommon. It is mostly related to testosterone levels (i.e., just being a male), and most of us want our testosterone. Persistent acne (and a specific late form of it called "rosacea") are quite treatable with simple antibiotics and topical solutions.
Blame genetics. It is not uncommon for people in their 30's to still have acne; although it should be much less than your teenage years. A lot of this is due to genetics, as most patients with acne in their 30s report family members with the same problem.