Todoist kept losing my todo items when they were stacked below each other in a two-level hierarchy (it might have been a keyboard shortcut or an error on my side -- we've ran through this with their customer service without any luck, but that's not the point).
With my broken Todoist I've avoided creating multi-level items and eventually cleaned up the list with this one question: is this task something I'm actually going to do?
If the answer is yes, then it goes to the list.
If not, then I discard it right away.
It's surprising how much of an anxiety relief this is. Todo apps tend to offer ways too many options, which makes you use them as backlogs or even notebooks. In my case, all those items were actionable - I've read GTD too -, the items just weren't important enough at most times. Now I get rid of the unimportant items on-the-fly.