This is not a valid excuse to go into asshole territory. Occasionally, you might not be in a position to understand why things are done a certain way - mostly because of inexperience, or your higher-ups might not have the time to explain the rules to you. Some examples might include regulations or standards.

It's alright to be humble and recognize that you may not understand some things sometimes. That's actually how you learn, and avoid pissing off your colleagues.