your boss may have a personal bias against you (even if subconscious), especially when taking into account racism or sexism, etc. So your salary being dependent on this person's appraisal of you could have nothing to do with your performance after all.
There are enough regulation and pressure on the salaries. The standard of living of decreasing everyday. What should be dealt with is companies that are not paying their taxes (Facebook paid £4,327 corporation tax in 2014 in the UK even though total profits for the year were $2.9bn).