Wood furniture and cabinets are a beautiful thing, especially when they are made well. I'm sure that you've noticed a time or two that the face of a cabinet shows few knots, and some table tops show the same.
I remember from my days on the sales floor (2000 – 2004) that some customers wonder why their table had more knots, or less knots, than those on the showroom floor. The same question areose from customers interested in high-end granite table sets. The answer is simple. God made it that way. That's not sarcasm, that's reality. When stone is cut from a mountain in India that piece of stone is going to have different character than the one cut from the next mountain over. The same goes with a wood table. Each tree is a little different and the character is to be enjoyed as a part of creation. Do not be alarmed if you buy new cabinets or furniture made of real wood and there is a big knot right in the middle of it. If you are ready to buy a real wood table or a granite kitchen table, be prepared to enjoy years of nature right there in your home.
If you want consistency in your table top, then you may need to start shopping for tables that have a laminate, Zodiaq or Corain top as they will look almost exactly the same as the sample or display piece. Be Forewarned, Corain and Zodiaq are pricey, and laminate tops are rare, but they are non-porous and more resistant to stains and water marks.