What Bothers Me About Spectral Lines

this kind of bothers me. We can tell all of these things about a star by looking at spectral lines. But this can be effected by the dopplar shift. So you have to fix that. And the according to the Zeeman Effect, the presence of a magnetic field affects the spectra also. Its just kind of annoying. We have ways of finding out things, but all this other stuff keeps getting in the way!!!!