This is totally subjective: everyone has a different comfort zone. I started thinking about hot and cold. Using a small heater or fan in the area you do your crafting. If you get too cold, your fingers don't cooperate and that is NOT a good thing for most any craft. Too hot and you'll just feel miserable, sweat will drip off your nose onto your craft and ruin it.

Your comfort zone however may have nothing to do with the temperature. It may be with what you are willing to attempt, or whether you want to do in private where folks can't see if you mess up, or only doing with someone else to help, or doing only for gifts and not for resale, or only doing one of an item and going on to something new, or having an entire area devoted to crafting, or always being content to use a corner of the dining room table. Bottom line, comfort zone can mean a multitude of things, depending on the situation, location, person, avocation.

Bottom line: You like to craft? You want to craft? Pick something that interests you, pick a spot where you can be comfortable working on it, pick something that looks doable and won't overwhelm you entirely. Then don't forget to be physically comfortable! Dress with comfort [and safety] in mind. Ready? Good! Don't be afraid to expand your comfort zone next time!

[Don't forget proper ventilation, particularly important for some crafts.]