I really like contrast stitching, especially on black or other dark bags. It makes it look a little more casual, which fits my wardrobe better. Of course, it depends on the bag itself, too, and the colour of the stitching. There was a black leather hamptons tote a while back that I loved but it had blue stitching. That would've driven me crazy because I never wear blue and even though it was subtle, I would've felt like it was clashing with everything I own (I wear lots of reds, pinks, greens, etc.).