I guess the same thing occurs in recipes. One of my daughters does not follow a recipe. I like to make things the way they are written the first time and then change it if I don't like it. That said, I have been known to leave out things from recipes (such as walnuts or chocolate chips) because I just don't like them.
There are some things that are improved by changing - or they can go completely askew, especially with food. Not too much can be harmed if you are changing a pattern using fabric - especially a quilt.
Recently, I started a quilt that was a block of the month. I had kept the pdf patterns because the subject matter was cute. Squirrels. The BOM was Bunny Hill's Henrietta Whiskers. I will change the name to something like Henrietta and Friends or George and Friends. This quilt has a lot of pumpkins in it - and stars. I want it to be more squirrels and less pumpkins. This idea came to me after I visited the Flikr site that had photos from those quilters that made the quilt when it first came out. There were a few quilters whose work impressed me because they didn't stick with the pattern.
Penny, of A Quiltmaker's Journal, decided to use a bird instead of a squirrel. I don't think the quilt was ever finished but she did manage the first block.
Marijke did finish her quilt and she changed it quite a bit. I particularly the fact that she got rid of the house at the bottom of the quilt and combined two blocks to add a pumpkin chariot being pushed by a squirrel and led by two black birds.
Kathie, who lives in Australia, made her quilt very distinctive. Her fabrics are totally different and she changed the original pattern quite a bit. She even made the house look like it sits in the Australian outback.
So, you see, even if you use a pattern as a jumping off point, you don't have to follow it exactly. Use your imagination, take out what you don't like and put in what you want. There is no one to tell you that you have to make it in the same dimensions or use the same colours.
This is the bear quilt that appeared in Quilter's Newsletter (I mentioned it here.) I remember showing this to someone and they really didn't like it - mainly because of the colours. It is not quilted but tied. The pattern is quite nice but there are some people who just cannot visualize it looking like something else.
This quilt was made by my friend Marg. The pattern was used as a monthly block draw, in the early 1990s, at one of the guilds that I belong to. Marg won them and then, because she likes bigger quilts, added a few of her own bears as extras and then finished the quilt. She held onto it until she had a great grandchild and a year ago Christmas, it was delivered to the little boy.
Same pattern, different fabrics, different size and a different look to the quilt. So, go ahead and change it up. Make it your own. That's what makes things interesting.