Automated calculation of matrix elements and physics motivated observables

The central aspect of my personal scientific activity, has focused on calculations useful for interpretation of High Energy accelerator experimental results, especially in a domain of precision tests of the Standard Model. My activities started in early 80's, when computer support for algebraic manipulations was in its infancy. But already then it was important for my work. It brought a multitude of benefits, but at the price of some inconvenience for physics intuition. Calculations became more complex, work had to be distributed over teams of researchers and due to automatization, some aspects of the intermediate results became more difficult to identify. In my talk I will not be very exhaustive, I will present examples from my personal research only: (i) calculations of spin effects for the process e+ e- to tau+tau- gamma at Petra/PEP energies, calculations (with the help of the {\tt Grace} system of Minami-tateya group) and phenomenology of spin amplitudes for (ii) e+ e- to 4f and for (iii) e+ e- to nu_e bar nu_e gamma gamma processes, (iv) phenomenology of CP-sensitive observables for Higgs boson parity in H to tau+ tau- , tau+- to nu 2(3)pi cascade decays