Who doesn't like their friends to agree with them? Even if you
do not agree on their viewpoints, and you do not feel like sowing
discord or being an arse, just say "yah, i think so too lor". Heck,
just make them feel better because that is what they want to hear,
not something that is opposing their viewpoints.
Unless the issue is something i feel strongly for, i would just
heck and go with the flow. Save yourself the trouble.