Yes, you'll find that condition is everything.If you see FDC (fleur de coin) against a coin it means that it is in such a perfect state that it's better than an ordinary example newly minted!
The other big negative is cleaning. A coin that's been cleaned with Brasso to make it clean and bright is rendered almost worthless, not literally so but compared to one that still has the patina of age.Collectors like the brown colour which is the natural discoloration that happens over years.
You might therefore find a 1797 penny which is worth only �20. A lot of 'cartwheel pennies' were made in 1797 and 1798.People liked to keep them as curios because of their great size and weight .They were unpopular coins at the time, because of that size.