I agree. I had to leave my comfort zone to run a marathon, or go to grad school. I still enjoyed the challenge, venturing into the unknown. There was no suffering. I never subscribed to the no pain-no gain nonsense I heard in the 70’s. With running, if you run whilst in pain, you get an overuse injury! I bore some discomfort without hurting myself. I ventured out of my comfort zone, but with common sense. The challenge helped me to feel more alive, built my confidence. It was an adventure, whatever the outcome. I have to leave my comfort zone to seek a relationship. It’s a risk, of being rejected, meeting more strangers, enduring more anxiety. My current comfort zone is isolating, feeling stagnant. My best example: I have to leave my comfort zone to get off these toxic psych meds I’ve been on for two decades. Seeing a holistic practitioner instead of the mainstream drug dispenser/doctor. Venturing into the unknown, it feels scary. I’m chasing a better quality of life, not riches. My comfort zone is not one of happiness or serenity. It just feels safe and familiar, minimal unknowns or surprises. As mentioned in the comments, it depends on one’s definition of comfort zone.