# Usage of commas in Japanese sentences?

This might sound like a strange question, but how does the usage of commas differ when used in Japanese compared to English? I believe りんご、オレンジとバナナ wouldn't work, but that it's OK to list like りんご、オレンジ、バナナ or りんご、オレンジ、またはバナナ. When should りんごとオレンジとバナナ and similar be used instead of commas or vice-versa? I've heard that going e.g. 分かりにくくて、読みたくない with i-adjectives isn't correct but 分かりにくいし、読みたくない and 分かりにくく、読みたくない is. I'm guessing it's OK to go 簡単で、特に問題はない and 簡単し、特に問題はない right? Additionally, what is the meaning of 、。 at the end of a sentence, e.g.　気にしてなかったけど、。? I think it might have some kind of emotive effect, so I think I'd translate it as "I didn't *really* care though" (for emphasis.) I might translate 、。 as "I'm flustered that..." in some other contexts but I'm not sure.