Well, one of the life lesson everyone learns sooner or later is that you cannot please everybody. Conflict and competition of all forms exists at every level of society and in any realistic system, someone would be unhappy about something.
It is necessary to differentiate "necessities" with "preferences". For example, having enough food to eat is a necessity. Having a four-star restaurant level meal every time is a preference. Historically speaking, a nation's stability is generally not threatened by unhappiness as long as all the necessities are filled.
Now, on the topic of mechanism to express one's opinion, election certainly is a potential tool of doing that, but if you rely on that as the end all method to express your interests and needs, then you are in quite a bit trouble. Because, elections are ultimately a legal way for larger group of people to overrule smaller group of people with their opinions. Take US' elective procedures, for example, US state level election is winner takes all. This means as long as you are not the majority party within the state, having 1 million voters is no different from having 0 voters. Also, elections only occur once every four years. This means in order to express an opinion, you require four year of waiting and even then, there is no guarantee your voice will be heard if you are not the majority.
Plus, you know, the fundamental purpose of having an election is picking a suitable candidate to administrate your nation. Since personal interest of individual is not necessarily aligned with long term interest of the nation as a whole, it can actually be detrimental to use elections to express your opinion. A good example is Greece (or lots of other European nations really). The voters want more social benefit, more tax cut, more vacation and more freebies and they expressed that opinion through their election, but what Greece actually SHOULD do is cutting benefits, makes the lazy bums to work more, so the nation would actually have an economy left, but since the voters wants social benefit, the politicians are left with two choices :
A.) Ignore long term national interest and implement benefits, pleasing the voters in short term, but ruin the economy in the long term and ended up making the voters angry at them for ruining the economy.
B.) Lying on health benefit and cut them as soon as they get into the official, this may help the nation in the long run, but their personal career is finished. The voters will vote the next politician that promises more and the cycle repeats.
It is like a no-win scenario.
So what should we do? Well, the Chinese's answer is that while we most definitely need some ways to hear people's opinion and preferences, it is not going to be bundled with selection process for leaders, because that is just asking for trouble. Common method include active survey, in depth reviews with local representatives and administrators, inspections, hotline reports, etc, etc. What is the center idea from all this? Balancing the needs and wants of a nation is a complex, ever changing task and there is no easy or single "fix" that all solve all the problems. On this topic I must mention the Indian PM Modi. I have read quite a lot of posts regarding to hopes and wishes the Indian people have for him, but my observation on the issue is that they are often asking too much for one PM who may or may not have even a decade of time in office. This mentality of one good leader will fix everything is pretty much the same as the belief that elections will fix everything and is generally a disappointment waiting to happen.