I've lost count of the amount of people who say "But...why would you charge me? I'm your *however we happen to know each other*".
I knit, I sew, I occasionally take old jewelry and make it into something new (but this is very occasional and usually just for personal use), and for my job I write and I also am a musical therapist (and can play several instruments).
I love to knit, it's how I distress. However, I live in a warm climate and frankly between the two of us we only need so many hats and scarves. So I often knit up hats and give them to my friends or their kids. Recently I had a friend have a baby (in May and he's cute as all get out!), and when she told me she was expecting a boy I made up a few baby hats, two pairs of booties, and little stuffed animal. She's since asked if I'd mind knitting her up a few more hats as the ones I made her were awesome but he's getting a little too big for them. She offered to pay me, or at least pay for my supplies. I have a huge stock of yarn (given to me by a friend of my mom's whose a knitter too), so I told her to come over and pick out what she wanted and I'd knit them up, no charge. This is mostly because the same woman does my taxes, my partner's taxes, and my business taxes for a very very small fee (seriously, H&R block would charge me triple), so I'm happy to help her out. Plus, she offered to pay, and I need to whittle down this yarn.
Now another friend finds out I'm doing this for her (I dunno how, friend grapevine I suppose) and texts me to see if I'll knit a few booties up for her two daughters. She's very specific on the yarn she wants, how she wants them done, ect. So I tell her she'll need to pay for supplies (I can get them or she can her choice), and I'll need X amount for my time. Her response was that I was doing it for first friend for free. I said no I'm doing for tax perpetration services, and she's just picking from supplies I already have, plus hats are much less involved. She huffed, puffed, and said she'd just buy something off etsy, awesome, have a great day.
I get hit up all the time for "Can you write my business proposal", "Can you teach me to play an instrument", "I need this tailored, can you do that?". I don't mind doing favors for friends occasionally. And I'm all about trading. For instance, my partner and I get our hair done for free because I helped the woman who cuts our hair with her business proposal and am giving her daughter guitar lessons for free, and my partner built and designed her webpage for free. I mend all of my mechanic's clothes and fixes our cars (everything but oil changes) for free. I love trading. I have a skill, you have a skill, lets work together. But "Do this for free cause you love doing it", nope.
And my poor partner. She's a programmer with a lot of web design background. If anything happens to anyone's computer ever, she's getting the phone call. And they expect her to do it for free. She won't. She'll give them a discount usually, but they're going to have to pay something. Really has made those hit ups for free fixing fewer and further between. She'll still get the occasional "Ok, it's doing this, what can I do?" call, and she'll give them advice but if you want more then that, it's probably gonna cost.