The pilot warned us as we approached DEN on SWA last month that it's usually rough coming in. Soon, we hit a pocket. Man, who had not fastened belt even when requested, hit underneath the bin. His laptop on the seat in between us may have flown up but what I did notice was his I-phone went up, smacked me on the forehead and crashed to the floor. Next time I'll try to sit next to a more thoughtful seatmate with a higher IQ [or I'll call the FA for support].