Proverb of the day :- There is no rule without an exception
Meaning / example :-
Just because a rule or law says something is always so, it isn’t always the case as we sometimes discover that circumstances change or are not how we thought. For example we knew that all fish live and breathe in water, however we have discovered some fish that do not always follow this rule. For example the mudskipper fish (periophthalmus) can climb trees and breathe in the air. This proverb isn’t used very often, but may be quoted verbatim when trying to figure out a problem where some element of the puzzle doesn’t seem to adhere to given rules.