I spent maybe 5 hours programming Silver Revolver (originally Russian Roulette) http://silverrevolver.com/ and it has made probably $30,000 over the last year, most of which was during a two week period when it was on the top 100 charts. I'd say I got pretty lucky.
Why would you not care? If someone thought that an app that I wrote sucked, then I would definitely want to know why. I would strive to write only quality apps and I could use the feedback to make my next app NOT suck.
You made 30K; good for you and congrats. Why all the snark here?
Simple and mindless(pardon not meant negatively) sells. Make apps for the audience who buys apps; males 18 to 34(though 34 might be a bit high) if you aim is to money. Something that makes people laugh and want to share it with their friends who buy it and share it with their friends and so on. iFart & Fat Booth(though idea is mindless but tech isnt) are further examples.
Why did the "No offense, but that app really blows." comment got down voted, and the "i think it's pretty cool" comment up voted? They both voice opinions, only difference: one is positive, the other is negative.
It is downvoted because it's a useless criticism with no value to anyone. Original poster "put himself outthere" in a way that is helpful to the community, and that guy was just trying to be mean and probably hasn't done anything himself. Downvoted to show original poster that we appreciate his response and do not support troll-like behavior.
Pointless negativity is generally much worse for a community than pointless cheerfulness. You're allowed to dislike anything at all, but this community requires that you express that dislike in a way that's a little more thoughtful than "Your app blows." fairlyodd's comment was wildly inappropriate for the context it was in.