The most common logical fallacy I see in the wild is confusing "if X then Y" with "if Y then X" or "all X are Y" with "all Y are X". Another one I see a lot, particularly in the news, is assuming correlation is causation.
Sunken cost fallacy. There's a lot of ppl in my life unhappy with where they are but they're too afraid to make a change just because they've already put so much time into it