Is my gaydar broken?

This is my very first post in English. Correction: my very second. It feels, however, as if it actually was, for this time I gave some more thought on what I am writing. I'd like then to begin by explaning my title choice. It was indeed the reason I flopped the language of my blog. I learned this word 'gaydar' when I was watching the comedy series 'Will&Grace'; in fact, the characters repeatedly used this expression, as one's sex orientation status was always on the spotlight (when it was not crystal clear, of course!)
Sometimes, I catch myself trying to be certain of things. I do that quite often, actually. And I'm afraid that's so in that I'd like to be able to rely on myself without much hesitation. I do realise that's not really possible - possibly. But if I think it through, it is not too difficult to see I may have a point. There's no actual way to be sure of things - many philosophers have taught us that -, though some would disagree. I wouldn't care for them, really. Righteousness would stop me from being so proposturous, but that's too far-fetched an idea. Be as it may, I'll still try to figure out one's orientation. Had I something better to do, I wouldn't be here writing this very post.