Here's the deal, we all want to cash out for as much as possible and no one likes the feeling of making X, when they could have made x+10. To make matters worse, X is a lot of money, and we certainly don't want O. It's very natural, but can be very frustrating.
You need to ask yourself how the money you could take off the table now will affect your goals. If you could take some money off the table now, what would you do with it? If you sold it all now, what will that mean for your financial position. Then, ask yourself if that position works for you...as opposed to asking yourself would you be better off with 10%, 20% or 100% more.
Money is a tool, it's a means to an end. Get rid of the more is always better mentality. When you change your perspective, you'll be better able to answer your own question.