In its main usage, /magari/ has the meaning of an impossible wish, it expresses a
strong wish for something that appears quite unlikely to happen.
Sometimes the wish could actually be realized, and sometimes the wish is towards the past, therefore is just expresses an opinion, as the past can't be changed.
-- magari nevicasse, saremmo tutti a sciare sulle piste.
-- magari fossi andato prima in Canada, avrei fatto da giovane un lavoro migliore!
-- magari riesco a parlarle di nuovo, e forse a conoscerla.
Somebody uses /magari/ just to express /forse/ (Eng.: maybe), but in my opinion it is not correct, as it
steals from /magari/ its meaning (from its Greek origin) of happiness and of some good event;
it is (always in my view) a way to use a word with more than one meaning, to express a simple meaning. We already have 'forse', or 'probabilmente' or 'puo` essere' or 'puo` darsi' and other simple expressions for the meaning of /maybe/.