If you create art, you have to like spending time with yourself.
Some of us love to paint, draw or write. A big inspiration to write is the fact, that the stories you WOULD have wanted to read, are not out there yet. That's why you write them. Same goes for painting/drawing. The fact that you would rather write/draw/paint than....lets see, go to a big
If you paint or draw and pursue it as a professional career it is because you really like doing that. You like making art so much, that you even do it although it can be hard and frustrating at times. In art school I had a time that I got so frustrated by my teachers and assignments, that a friend of mine said 'I don't get it. If you hate making art so much, why don't you stop!?' Fellow artists know what I mean when I told him 'I could never ever do that!!'
Most creatives live in a bubble. It can be hard to grasp why you do what you do for people outside of this bubble. Especially friends and family who have a normal day job have a hard time to understand working freelance, let alone working as a creative freelancer. Sometimes there will be days (or weeks) when things go slow. You finally have a lot of time to work on your personal projects or your website OR to tend to some other things (spring cleaning the house). And then there will be the crazy times, working several client jobs at once, calling non-stop, sending out emails non-stop, being stuck to your phone because you wait for important calls, short nights and ordering take away because you just don't feel like cooking on top of everything else. Sometimes it even means working through the weekend or holidays. Sometimes you will have to cancel a night out with friends because this commission is juicy but sadly has to be done in 2 days (in editorial it's even shorter). Sometimes friends don't understand because 'Your client just can not ask of you to work those crazy times!!? Right!?'
This is only part of it. Living a modest life, so that you don't get into trouble when a client drops you, or working a day job next to your profession are other parts people tend to forget. Not taking part in sports or activities that might endanger your hand/arms/eyes is another consequence of wrapping your life around the fact that you make art. Instead of pursuing these'dangerous activities' you do boring exercises against the inflictions of working as an illustrator.
And although this might sound horrible or weird to some and although others might not understand why you go through with all this when you could just have a normal nine to five job and enjoy holidays and nights/weekends off, you still just LOVE what you do. More than regular work times, more than weekends off, more than being outdoorsy, more than a sport you would like to pursue but is too dangerous for your hands.
(That's me being outdoorsy....)