What’s a word or expression you really struggled with at the beginning but now find surprisingly easy to remember?

Personnaly, I remember having a really tough time with 劇場版 (げきじょうばん) the first time I encountered it in からかい上手の高木さん, however when I watched 劇場版 どうぶつの森 a few days ago I just read it straight away without hesitation, SRS sure is amazing…