I noticed few years ago that there is a word (actually a verb) in the English vocabulary that I rarely use at the first person. In fact it's been going for a very long time, as this was already the case in French, ever since I was very little. This verb is "to believe". This pattern of (non) use of a particular verb has always been an untold personal policy which only became conscious few years ago.
I do not have any other word which had an associated policy, except the word "femme", which is the French word for both "woman" and "wife". I spent my entire childhood convinced that one needed to be an adult to pronounce it.
Coming back to "believe", in fact there are cases where I can use it. For instance, to refer to things that might or might not happen in the future. For instance, I can say "I believe that [ put here a random sport result from next week's championship finals ]", but I never use it to make factual claim about reality (use an intuitive natural definition of "reality" here). Above all claims that are controversial (for instance, claims related to mystical or supernatural entity or events, more generally claims that seem to escape the perception of everybody except the people who make them).
By the way, I wrote "i can use it", but in the above cases, most of the time you will find me saying "I think" instead of "I believe". Indeed to emphasis the fact that there is usually a good reason or a reasoning leading me to "believe" that Team A will win over Team B. A reasoning which might be incorrect (this is why I would not bet money on the outcome of the game), because my knowledge of the two teams is limited, but still a reasoning.
On the other hand, there are moments where I simply refuse to state a belief in one way or another (and this is really more than "avoiding", it is "refusing"). For instance, when the faster-than-light neutrinos thing came up (we now know that it was a fault in a detector, resulting in a mis-measurement), then I simply refused to state that I believed (or thought) whether or not the newly discovered speed might be legit. In those moments, I tend to put my reasoning on hold until the end of the investigation. This is a particularly important psychological trait, because it expresses the fact that I know that I am not a part of the equation, and that the universe doesn't care what I think. Stating that I believed or not that those neutrinos were going faster than the speed of light, to me, was not only useless, but would only have added unnecessary noise to the problem (even though, I would have been the only one in this case to hear the noise). To me, the correct attitude was just to wait and see what the investigation would conclude, rather than starting to live in my alternate reality. Even though that alternate reality might (by accident) turn out to be valid. More generally I do not make claims hoping to be right. This really contrast with some of the religious folks who turn wishful thinking into a full time job (and make factual claims about things that are for me still under investigation, for instance the origin of the universe).
Anyway, all this came up because of a small online chat with an (asian) friend this afternoon, which went like this... (slightly edited)
Friend: Do you believe in feng shui ?
Pascal: Not really....
Pascal: I usually do not choose to believe in something or not. There are only things I understand and which make sense, versus the rest... If one day somebody explains feng shui to me in a way that makes sense, then I will start believing it.
Friend: [ long list of brochure points about why feng shui is valid ]
Friend: ... and beside my friend says that this helped her a lot. But you probably won't agree since it's not scientific...
Pascal: Something can make sense without being scientific. But for the moment feng shui doesn't make any sense to me. Additionally, I never trust people when they say "[whatever] helped me a lot". Often their beliefs affect them in non trivial ways (see the Placebo effect for instance -- and don't even get me started on homeopathy), but it doesn't mean that whatever they postulated the existence of, actually exists.
Pascal: The belief in God works the same way. You believe in religious myths, this does things good to you (well, sometimes does things good to you -- and more often than not, unfortunately, doesn't do any good to the people who do not share your beliefs, as we saw so many times in history, and more recently with some freaks' beliefs that some specific people cannot be portrayed), but this doesn't mean that God exists. Unfortunately, many people take the fact that their beliefs affect them, in what they see as a good way, as the proof that God must exist.
Pascal: If I start believing, really believing, that I have an amazing girl friend waiting for me at home, and this belief happens to makes me very happy all day and put a smile on my face in the office (this latter fact being, by all regards, arguably a good thing), this doesn't mean that she exists.