It took a lot of practice to actually get all of the syllables of a complicated verb ending, especially some of the nuanced ways of saying maybe, there are so many common ways to hedge your predictions of the future. The double consonants really were difficult to get down.
I spent most of my time speaking in the wrong honorific, even at a basic level you are taught at least 3, and they are applied to every sentence. Thankfully where I was foreigners weren't super common and were always given a large amount of leeway in mistakes with the language/culture.
I still think some phrases or concepts are funny, i.e. to say something tastes bad you say there is no taste. To say you are hungry you say that your stomach is empty, to say you are thirsty you say your throat is dry.