Perhaps you should read some of the books written ABOUT grammar. Several different types of grammar, there is even spoken grammar. Read some of the stuff from that doyen of good sense Noam Chomsky. But (never start a sentence with a conjunction!) more importantly the rules of grammar are the bones upon which we hang the wonders of spoken and written communication. Within the words we use every day we can find our history and our culture. We can look at place names - I mean real place names, not American fast food names - and see from their formation, spelling and root who lived in a place, from whence they came and from there, how we came to be. Chester/caster/castre show Roman military bases and forts, -by is a settlement, - ley, -land and others show the influences of the ancient rulers of Britain, words with a silent 'k' show us french and latin derivations (morphed from a hard 'c'). In America borrowings from Native American and South American languages shape our view of ourselves. We can find references to foreign trade and influence and the evolution of all societies. Even conventional grammar marks the influence of ancient Rome and its realms throughout Europe and North Africa.
If you wish to ignore the rules of grammar - written and spoken - if you wish two tern yore bach on conventional spellin then you might as well ignore you customs and traditions, your racial mix, your culture and who you are.
Quick question (no googling): How many tenses are there in the English Language? First answer gets a prize of an imperative verb and a preposition.
No. its late. I will not go back and proof read that.