Buying a pattern and finding out that there is no real pattern, just instructions on how to make a pattern and instructions on how to do the sewing. I think that if there is not a pattern in the envelope, you should have to call it an instruction pamphlet! I am going to ask from now on, since it has happened to me twice and my disability makes it difficult to actually make the pattern.
This reminds me of another one: Finding a really cute cross stitch design but the pattern not being crisp enough to clearly see the grid lines when printed out, which makes it hard to tell how many stitches there are in a row or column. Or when there's no clear color key, either, especially when there are a few different shades of a color.
I suppose part of it is because some of them are free patterns and you get what you pay for. In some cases I've gotten creative with some good results, actually. Like there was one I did recently of a mermaid. It involved a few different colors in the tail. Instead of changing floss a few times to finish the design I tried a technique called blending that involves a thread of regular floss and a thread of metallic floss.
It ended up looking really neat, as I used a multi colored metallic floss so the stitches of the tail looked like sparkly scales.
But not all patterns are as suited to such adaptions.
As for hair growing back...there's a girl in our church who cut her own hair. It did not look good and one woman said "Well why don't they fix it?" Well the girl cut it pretty short and I guess they did fix it as much as they were able to and she still looks adorable. I know if one of my boys did that to their hair I'd have to take them to a barber as I certainly wouldn't be able to do any better than the child did.