When I look at the difference between the conservative and liberal agendas here's how I break it down. Its an oversimplification but it covers what I feel are, at least, the base ideas that drive each agenda. Defining the agenda itself, frankly, is impossible. It grows and adapts with each new policy issue. What can be defined are the core values that drive each of these agendas and through them one can discern the agenda's nature.
I apologize if much of this sounds like stating the obvious but I feel its really the only way to describe the agendas. Also, I'm well aware that I'm generalizing. The agendas are generalizations. Not every Liberal or every Conservative believes the exact same thing. Also I would have you keep in mind that I'm extremely Liberal. I have no issue with Conservatives but I will admit to having an issue with many modern Republican politicians and their individual agendas. So if my views start getting a bit skewed, that would be the reason.
Conservative Agenda: Conservatives want to return things to the way they were. Pure and simple. At its most extreme it can be called Reactionary. They want old style values, old style business, etc. In addition to that, true conservatives (I differentiate between them and certain modern politicians) truly want limited government in a sense that, when looked at from a positive view point, can be labeled 'the freedom to do things myself' and, from a negative view, can be called 'only the strong survive.' You earn it, its yours. Its not the governments job to help you out. They favor a strong military, taxes that are only to the level that are necessary to sustain our government, and a focus on America itself rather than America and the entire world. They believe that if America is strong we will be in a better position to take action around the world when that action is truly needed. They believe in keeping the rich rich because then they will spend large sums of money on goods and services that'll work their way down to the poor, stimulating the economy in the process. Also, the rich earned that money and since the conservatives want to run smaller government, they don't require it anyway.
Liberal Agenda: Thank you Obama for making this sound cliche, but Liberals want change. At its most extreme it can be called Revolutionary. They believe its necessary for our values, business ethics, laws, rules, etc. to evolve over time. In addition that, true Liberals tend to believe in big government. I know, that's a talking point these days but hear me out. They believe that sometimes, the average individual may be incapable of doing one thing or another himself. They're not saying the average person is incompetent, but rather that the government should provide for its people when such providing is needed. Whether it be providing the poor health care or insuring that a company's consumers and/or employees can expect a certain health and safety standard from that company and its goods and services. From the negative point of view they call it 'big government' (or, these days, socialism). From the positive point of view they call it 'helping people that need help.' Lose your job? The Liberal agenda is the one that says you'll have unemployment compensation until you find a new one. Its the one that makes Social Security, Medicare, Medicaid, heating assistance, etc. possible. They too favor a strong military but believe that the conservatives overcompensate in this department and thus tend to favor a certain amount of cuts to defense. They favor higher taxes as they tend to fund more programs, all of which require money. They believe in a global approach to American politics where even if it means things are going to be a bit harder over here, we should work with the global community and maintain strong, foreign ties. Thus, if a global crisis does occur, we have good relations making it easier to work together and resolve such a matter. Despite it also having become a real negative term they believe in 'spreading the wealth around.' If you have more money, you should be taxed more. Thus said money is reallocated rather than hoarded or spent merely amongst the rich and the economy is stimulated.
How are the agendas similar? Well at the core, neither is intended to hurt America. Its simply different paths to solving the same problems. Its not like the conservatives want to plunge us into the Dark Ages or the Liberals want to turn us into a Socialist nation. At their core both hold basic, American values to heart and work to employ them and to allow the people of the nation to prosper. That said, as the agendas are generalizations and ideals, often the actions of individuals who's sincerity can be called into question come into play. For example, there's a difference between not overtaxing the rich, and not overtaxing the rich AND giving them massive tax breaks while in a recession.
Are the agendas mutually exclusive/can they be reconciled? Its going to sound strange but yes to the first question and yes to the second. Many people would say no to the latter but I disagree. Really, its all a matter of how you frame what you're trying to do.
There are ways to meet in the middle. Some of our countries most notable politicians were quite skilled at it. Really it comes down to how you frame your argument. For example, conservatives are against raising taxes. However, they are pro American values. There have been presidents who have made the case that sacrifice and interdependence are important American values and through this argument have gotten conservatives to agree that higher taxation is necessary. There's also the 'more taxes will help strengthen America' argument. It doesn't work with many modern politicians but as I've said, I don't consider many of them to be a true representation of conservatives.
Going into all the other issues here could be a book in and of itself. Suffice to say, the agendas cannot be implemented at the same time. They are often opposites of one another. However, there are ways to compromise and make both sides happy in the process.
Do I think these agendas are realistic representations of personal opinions? As long as they are not taken to the extreme, yes. This is where my issue with many modern Republicans lies. They take the conservative agenda and push it to a Reactionary extreme leaving them willing to do things like the aforementioned lower taxes and give tax breaks to big businesses, putting our country deeper into a hole. I won't dwell on this much as I don't feel this is the place for it. So, getting back to the question, I feel that the base ideas do tend to reflect personal opinions. IE: Conservative voters do place a greater emphasis on a powerful military while Liberal voters place a greater emphasis on social programs. Again there are many other examples but I won't go into them. The list could go on for miles.