For me it's not only interesting when i started having ideas (probably because I can't really remember) but also when I'm having "interesting" ideas...
For me it's mostly when I'm stressed out. For example when I was learning for exams I very often had interesting ideas I started to dissect and analyze. Even though the ideas were interesting and intriguing, I quashed most of them because from a business perspective (and that is my background) I could see the idea prosper. I too write most of my ideas down so I can use them later or use them as inspiration.
For me it's mostly when I'm stressed out. For example when I was learning for exams I very often had interesting ideas I started to dissect and analyze. Even though the ideas were interesting and intriguing, I quashed most of them because from a business perspective (and that is my background) I could see the idea prosper. I too write most of my ideas down so I can use them later or use them as inspiration.