The cost of adding a feature isn't just the time it takes to code it. The cost also includes the addition of an obstacle to future expansion. The trick is to pick the features that don't fight each other.
“I have three phobias which, could I mute them, would make my life as slick as a sonnet, but as dull as ditch water: I hate to go to bed, I hate to get up, and I hate to be alone.”
“Art must unquestionably have a social value; that is, as a potential means of communication it must be addressed, and in comprehensible terms, to the understanding of mankind.”