Grammar is very important! While it's true that spoken English (or any spoken language) may sometimes ignore grammatical rules, proper grammar is vital when writing. Otherwise your language skills would be considered very poor, even if you do speak the language fluently. Know the rules before you break them. ;)

it was both inportant. cowboy...

I would say the both. You will feel handicaped if you don't master both of them To choose between them, it's like deciding which part of your body is more important - legs or hands....