You can subnet however you want to. What is against the RFCs is having host bits being more signifigant than network bits.
Find the RFC on CIDR - classless inter-domain routing.
You can do whatever you want. 30bit netmask, no problem. Use subnet 0? Sure. 25bit netmask so you have a "high" and "low" subnet, no one would even blink an eye.
Problems crop up when you do VLSM and your routing protocol's not able to handle it, but even those issues you can get around.
If you don't like subnetting, stay away from networking as a career.