Constipation - I have thankfully avoided thus far due to my high intake of multiple kinds of fruit.
Gas, however, is something I have had in ample supply. Usually it's when I'm at home, and I can ignore the cats' judgement and pass wind freely. Usually.
But let me tell you. You have not truly lived until you have stood in front of 13 silent community college students, ready for you to start your lecture - and suddenly and overwhelmingly, felt the urge. That, my friends, was an unpleasant moment.