"Market Correction" - What's the big deal?

[Ali Dawood]

Sellers market, buyers market, market correction, etc. I am new to investing and have read several of these terms throughout this site and others regarding when to buy, when to hold, when to invest, when not to do anything. 

Am I too naive to simply ask: "What's the big deal?"

The reason I say that is my understanding of RE is that the trends go up and down every few years. Sellers market right now, buyers market in a couple years, then back to sellers market. I know we can't predict when this will happen but since we know it will happen why does it matter so much? I know there are ways to make profit in either market with varying strategies, so why are investors so worried about it?

Not looking for a right or wrong answer here, just varying views so other new investors and I can be enlightened.