You’re asking the wrong question
blog.aisleten.com
blog.aisleten.com
Holds true across nearly every category. Anybody who makes things and gets offended when people don't like it won't find it easy to progress.
Stay true to your vision, the first change you should make is when you try to use it, and it does not work well, or when the first people try to use it, and you are finding out that they are not doing what they should be doing.
As an example, I recently wrote an application. The application was designed to meet a need that I had that no software package seems to currenty meet - specifically allowing me to create a program to follow on my exercise bike at home whose idea of an onboard computer is a counter that gives a fake number of metres ridden since the start of the session. As a secondary goal, I wanted to use this app to learn Cocoa for the Mac, which would lead me into iPhone development. As a tertiary goal, I thought it would be nice to put the app on sale - after all, I can hardly be unique right? If I see the need for this app, surely others could too!
So, after three months of work, I had a pretty nice app. No known bugs, easy to use, reasonably pretty, but of course, hey, it doesn't do a lot except roughly copy the functionality of any half-decent exercise bike's on-board computer, so nothing special. I knew that the app was useful - I had been using it daily for about 2 months at this point, and it was actually really good at getting me to work up a sweat. But then I tried to explain to family and friends what this app did. Every single one of them wanted to know how you plugged the computer into the bike, which of course you can't do, because the bike has a brain dead onboard computer with no way of connecting anything, hence the need to write this piece of software (for the curious, the program simply keeps a running counter based on a timer and your program - if you've programmed a higher speed for a block of the program, the counter increments faster. The user has to keep the bike's counter up with the computer's counter).
The problem was that everyone has the model of the exercise bike computer that changes the gears of the bike the higher the bar is on the little readout. My system can't change the gears, not being connected to the bike, instead it just makes you pedal faster (which achieves the same goal of making you work harder). But because the app goes against what people expect, it was next to impossible to get them enthused about it without sitting them down on a bike, with the app running next to them, and making them do a program. Then they understood what the point was, but to this day I have never succeeded in getting someone to understand the app's main usage just by explaining it. I eventually decided to not put the thing on the market, because I couldn't see any easy solution to the marketing difficulties, and anyhow, I had already achieved goals #1 and #2 with the project.
All of that to say that asking for people's opinions on an idea is very unlikely to work very well, unless you have really good communication skills, and even then, the person listening needs to have a certain capacity to envision something that doesn't exist, and not everyone can do that.
Why does it suck? Because it doesn't interface with the bike. As you put it yourself, "it goes against what people expect" It's not that you should quit, but that you need to think about this ahead of time and figure out specifically how you're going to counter these expectations.
But I would counter your counter by saying that you identified late in the game that you were going to have a very hard time marketing the app due to people's expectations. Poor marketing and inability to get users to bite kills plenty of decent ideas. Not recognizing that early on is as damning as building something that collapses when you try to scale it.
I'm not saying your idea is a bad one. I'm just saying that getting criticism early on, even of a vague idea, can be very helpful. It can help you not only in implementing your idea, but also in implementing any marketing strategies or deciding how you want to position your product.