David Pulver said that he was told that GURPS Vehicles specifically couldn't use cube roots or logarithms. So there's tables like 1-9: 0, 10-99: 1, 100-999: 2, 1000-9999: 3 and literally "so on", which is a logarithm base 10 in table form.
That certainly wouldn't have bothered me, but GURPS...