Saying no to a friend can be one of the hardest things to do. But once you get past the hurdle, I think you'll find that your friendship, maybe even life, in general will benefit from being more assertive. If they're really your friend they will understand. It's not selfish to have alone time, everyone needs it especially artists. Just have tact, say it so that you won't hurt their feelings, ya know?
There are two perspectives on this question. One is your friend's perspective, and one is your perspective. If your friend asked me about the situation, I would tell your friend that he should not impose on you, because it isn't nice. But because you're asking the question, I will respond differently:
In my own life I have had this same problem. This is what I discovered: the best path to take is to say yes to your friends, except in the condition that saying yes to them makes you a worse person, or causes you to fail in your own responsibility. I had a friend who constantly asked me to hang out with him. but after hanging out with him too much, I felt like I was turning into someone very unpleasant. So now when he asks to hang out, I hang out with him for a set amount of time, and then I say 'no', I say goodbye and I don't accept anything he says to the contrary.
The reason for this is, that you really don't know the circumstances of the other person, and so a slight inconvenience to yourself could mean a world of difference to them.
Also, particularly because you're a Christian, I say my advice is best, because it's what Christ taught: If someone asks you to walk a mile with them, walk two miles
Thank you for sharing your experience on this. And I have actually came to the same conclusion in your second paragraph when I started noticing that saying yes was counterproductive towards my mood and having a good time. So I would notice that I was turning bitter and quiet although I did my absolute best to hide that from my friends although it didn't work too well. So that sounds like a good rule to abide by.
And I appreciate the Scripture at the end, it makes for good advice as well
You aren't being rude at all. There was a girl I knew a few years back that I was sort-of friends with. She got very attached to me and would stalk me online, call my house literally thirty times in under fifteen minutes, textbomb my phone, and otherwise stalk me. She found out what my email address was, and kept sending me emails if I didn't respond to her quick enough, or at all. She didn't understand when I tried explaining to her that I needed some time by myself. After a while, she got very rude towards me, constantly insulting me or putting me down when I was going through a tough time in my life. I asked her nicely to leave me alone for a while, but she couldn't take a hint that I didn't need to hear her insults and petty complaints because I was dealing with other things. When I wanted to spend time with other people, she would cry and make a scene, claiming that I was ignoring her. Finally, I told her bluntly (but politely) not to talk to me anymore.
Honesty is the best policy. Easier said than done, though. Don't let your friend push you around. There are more things in your life than just him, and you need time to do what you want.