Saddle sores are very painful and can ruin your ride.
A saddle sore in humans is a skin ailment on the buttocks due to or exacerbated by, horse riding or cycling on a bicycle saddle. It often develops in three stages: skin abrasion, folliculitis (which looks like small, reddish acne), and finally abscess.” (Wikipedia)
Even if you ride with the best quality, most comfortable chamois, your nether regions are continuously subject to heat, moisture, chafing and pressure – especially during wrong rides. If you spend enough time in the saddle, you’ll have to deal with saddles sores at some point.
Regardless of how small or big a saddle sore is, it can ruin a ride (or a few rides). Because they are so painful.
Image source: Alchemy Rider