It goes without without saying that when we express our opinions, that is what they are, so why say it? If it wasn't my opinion I wouldn't say it.
There might perhaps be some point, when it comes to a matter of fact, in pointing out that this time it's not a matter of opinion; but that isn't really necessary either.
And again, there might be occasions when we want to present some argument, as an argument, which we do not actually believe is true, and I do think that in such cases it is a good idea to point that out. (And in that sentence it seemed appropriate to add the qualifying phrase "I think".)
Incidentally though "you know what would be really helpful GUEST Date: 22-May-02 - 06:27 PM" - if you stuck a name or a number or something on your post as a matter of good manners and convenience to other people. (For example there is no way of knowing whether GUEST Date: 22-May-02 - 06:27 PM is the same as GUEST Date: 22-May-02 - 08:23 AM or GUEST Date: 14-May-02 - 04:48 PM or GUEST Date: 17-May-02 - 02:25 AM; not that it matters a great deal, but it is inconvenient, and distracts from rather more significant matters.)
But I think both those possibly fascinating topics are ones that might perhaps better be explored in a separate thread, rather than allowing them to hijack this thread. (And, perhaps rather naively, I'm assuming that was not the intention of GUEST Date: 22-May-02 - 06:27 PM)