Be straightforward about things. Example: If you don't want to go along with something you don't like, don't make excuses, just say "No, I don't like that".
Its not an unreasonable response.
The one exception is when a woman asks you if this dress makes her look fat.
I've received a lot of good advice, none any better than the other but this is something I was told many years ago that I always live by... Ask yourself, I know what I think but what do I feel?
The best advice I ever received is that it is better to come to what appears to be an agreement, but in reality isn't a complete agreement, then to refuse to reach an agreement until you completely and unambiguously agree. Reality is that 99% percent of the time, what you don't actually agree on will never be of any practical importance. Put another way, absolute certainty of agreement is overrated. The productivity of co-operation and "carrying on business" far outweighs the utility of certainty. This advice is equally applicable to one's personal life as well as in business.