Rick's beard is probably the most talked about of the show, but his transformation is also the most symbolic. Bearing in mind that Rick used to be a sheriff who enforced the law pre-zombie apocalypse, he takes his former occupations seriously, even after he wakes up from his coma in season 1. He came across as a very clean cut character (almost literally) who wanted to do what was right both morally and lawfully. However, as time progresses and the world falls into ruin, he realises that new rules now apply. He is not living in a world where there is right or wrong, there is just survival. The length of his beard and his haggard appearance symbolises his personal evolution as he is gradually becoming more savage and primal in order to protect his family. Not only does his beard make him look more intimidating but it also portrays how far he has come from his former self. He also looks devilishly handsome with a beard, but that's just a matter of opinion.
