Dialogue is very important. Without dialogue the story can't progress forward. Dialogue should convey an emotion and spark that said emotion in your reader.
Bad dialogue example: "ohh hai stayles stinklinski.. oh yea.. mai fave coler is paink."
Better example: "My favorite color...?" Why would he want to know that? Crap. I'm taking to long to figure this out, aren't I? "It's um... Pink."
Your story should be easy to comprehend what you mean and should be descriptive enough that the reader can envision the story playing out in front of them.
Mediocre example:
I loeked at Swuidward and saw hiss abz. "I wenna kizz yuo."
Better example:
Silence trickled into the room after Briana tells us that we need to split up into groups, seemingly echoing throughout the dwelling.
I see Brandon shift a little in the dark.
I swallow. Even though the wackjob who cut the power's identity still remains a secret, I know one thing for sure--they won't stop until we're all dead.
My hands continue to tremble as I take one small step forward. I suck in a breath. "Brandon?" I begin to ask. "Can I go with you?"
When writing, it's important to remember proper grammar. It might not bother you if you forget a quotation mark or two, but it'll definitely bother the reader.