I ran into an older gentleman at JoAnns the other day. He had a bleach stain on his sweater and wanted to cover it with a patch. so he ask my mom and I is just ironing it on would work. After talking about being sure the yarn wouldn't be damaged by the necessary heat and we got into a conversation on adhesives.
I suggested that he get the Patch specific glue because it was made for adhering to fabric. So the man, being a man, said that he had model airplane glue, so wouldn't that work. I reiterated that it wasn't intended for fabric and he could destroy the fabric or change the color; so he came back with "Hey, I know, I have a hot glue gun! that would surely hold it on." So we discussed the rigid nature of the glue. etc. You could tell he wasn't convinced, but finally my mom managed to talk him into taking the correct glue and if he didn't need it , to return it. I was really surprised that he just didn't use his staple gun or buy a buttoneer!