Running for example. It's hard to do. It takes preparation. You loose your breath. You might get sore. Well, it was like that at some point (or still is). Your brain put that thing outside the comfort zone. But running is good for you. After a week a running you start to feel better overall. After a week of driving (something in the comfort zone) you feel notning.

The comfort zone is not good in telling you what you should do or not do. Nor is it just these two categories. Stabbing yourself with a pencil is outside the comfort zone and bad for you. Walking is inside your comfort zone (running is not) but that doesn't mean you shouldn't go outside and walk. All the comfort zone wants, is keeping you inside of it.

The comfort zone makes it hard and uncomfortable to do stuff outside that zone, but it also gets smaller if we don't push it. Things that were right on the edge (but still inside) of the comfort zone suddenly take a lot of effort to do.

Decisions based on your values and traits you want to live, helps define what person you want to be. Be aware that the comfort zone won't help you with that. Try to follow these decisions even though the will be hard to do. But the comfort zone will expand and at some point the lifestyle you have adopted feels natural and you don't fight the comfort zone for that.