Asking for Suggestions

I come from a scientific (to be precise, mathematics) background. I have lately started getting interested in philosophy and read some Albert Camus, Marx, Sartre, Ayn Rand, Hegel, Niet. and Kant. What troubled me was that their ideas seemed a bit... unrealistic. They start with assumptions that I find are too loaded, and they develop them in a manner that is not precise.

So, which authors/philosophies that are closer to my "taste"?

You're reading (European) continental stuff.  You will probably like Anglo Analytic stuff better.  Try Daniel Dennett, Wittgenstein, Russell to a lesser extent.