I find it interesting how having different ideas on particular matters, from small things all the way up to a Weltanschauung, affects friendships. For most people, I think having very similar positions on most matters makes things easier - it's difficult to really understand people who are different. Beyond a failure of understanding, some people are offended when other people fail to come over their side after a really good argument, and then there are people who place so much stock in controlling one or more aspects of their social identity that it becomes an affront to them when other people fail to think about them as they wish. These pose certain amounts of difficulty in keeping society working smoothly. I suspect that one of the major sticking points that pushes random people into conservative camps is a dislike of expectations of uniform respect to everyone, no matter how bizarre their ideas are or how it might lead to internally inconsnstent positions (e.g. one liberal person believes and insists everyone believe X, and another liberal person believes and insists everyone believe Y). I think people need to develop thicker skins and carefully examine their value system to decide when people can't be friends - people who don't consciously do this, at least in areas where lots of ideas collide, risk losing people who might be good companions. It can be possible to simply not talk about some things with some friends, or instead to disagree passionately with them over matters, but so long as civility can be maintained and people can remember at the end of the day that one does not need to approve of all of someone's ideas to consider them a friend, things can potentially go much more smoothly. By and large, I think I've done a pretty good job at this over the years, and given the wide variety of differences I've had with friends (from the many different positions on Israel and Taiwan I've had, the different philosophies I've experimented with, etc) over the years, most people I consider friends probably are similar in these regards. There have been a few people I've ended things with, mostly when they did something I consider grossly unethical (far beyond the I wouldn't do it level), including a former close friend and my father, but people who would never do that under any circumstance strike me as people who don't really have values at all.
To go too far the other way and be a "yes man" is something that, personally, I find really irritating, at least partly because such people tie people down to whatever they believe at the moment, out of emotional concern for exposing their friends as sycophants or losing them should their judgement change. People should not often need to worry "What will my friends think?" or "I'll be letting people down" if they are considering reconsideration of some positions they hold/accept, or at least it should ideally be infrequent and scale to the level of difference.
At the same time, one should be careful not to interpret any of this as a call to give up on making one's perspective mean something in life or to cease pushing it (if necessary and as appropriate). People who would seduce us with "can't we all just get along?" and tell us to simply care about nothing or accept their "universal" values are just as problematic.
Incidentally, sycophant is a fun word - I had to look up the spelling because I don't think I've ever written it before.