Honestly, I don't think the signature actually does anything. Any of them that require a signature on a pad, I just do a short scribble, and it's fine. If it's a paper receipt (like at a sit-down restaurant), I usually just use my actual signature.
There was a comedy website a good 20 years ago at this point (Zug, if anyone else out there remembers them) where someone tested this by doing more and more ridiculous "signatures" every time to see if anyone called him on it. If memory serves, the closest thing he had to an issue was a store manager chuckling a bit when it devolved to him just straight up drawing dicks.