In-a-relationship personality

Relationships change us in several ways.
First is the change from a single person to a in-relationship person. It's not just in a name, but most importantly in the smell of the rose. You behave and think differently. You do different activities. You realize that for years of short relationships you have never really been in any one of them. Because this change has never taken place, because real closeness has never developed, because you didn't let it. And at the same time you are not entirely certain which you you liked more. But "the current's too overpowering; you don't have any choice...Danger may be lurking there, something that may end up wounding you deeply, fatally. You might end up losing everything. But there's no turning back. You can only go with the flow.." Should you regret changing or embrace it?
And then there are other changes. In tiny bits you start using the other person's language and a manner of expressing himself. You start prioritizing slightly different things, solving problems in a slightly different manner, communicating differently with your friends... You don't even realize at first, but in time you begin to see it. The relationship is changing you ever so slightly. And again the same question arises - where do I stop being me?

Public perception

I find that sometimes the people around you can tell more about you than you yourself. Can better predict, what choices you are about to make, even when you don't even know that you are going to be faced with a situation requiring a choice. Getting the view of the others can be helpful in realizing things.
At the same time, there is no judge harsher than your acquaintances. Even if you did nothing wrong, just a perception of possible misconduct of any sort means harsh judgement from a lot of people. And even if you explain over and over that there really wasn't any wrongdoing, the message reaches only part of those who have already made up their mind and sentenced you.
Weird, how the elderly more than anyone else seem to think that they know exactly what happened and why. My grandmother being one of them (and not the only one). She could see a small gesture, hear about a tiny detail and she was sure she knew the whole story. And even though she was so very kind to anyone, she would also judge based on her presumption of what has happened. Maybe, as we grow older, we also think that we know every pattern of human behaviour, that we can guess, what people did or say just based on a tiny hint. Can we ever?

Doubt

I am one of those people who doubt everything. You could say that doubting myself is just a manifestation of my low self-esteem and you might be right, but I don't stop there. From time to time I start doubting everything and everyone. I stop being certain about what I have experienced and begin questioning my judgement of events that have transpired and the bias in my perception. It is usually pretty hard to snap out of this circle of doubt. Once you don't trust anything including your perception, how do you build sensible view of the world... Somehow I have always found something, a steady point, basis to rebuild my world upon. But it leads me to a number of questions. Is it healthy to deconstruct, judge and reconstruct your world every now and then or is it harmful to your psyche and everything around you? Is it possible to live in this circle of doubt from time to time or will I just one day stay stuck inside, unable to snap out of it? Where do people get the confidence and, I guess, arrogance? How can anyone be certain that their perception, evaluation skills and world views are the best possible ones? And if they know they are not, how can just go on living without trying to find ways to improve them?