The really annoying part is when you accidentally click some link that opens in the same tab, or click back, or do anything else that needs to reload the page to open the feed. You effectively lose all progress you've made reading through it.
This is my biggest problem with it. I don't mind so much that if I force refresh of the timeline it changes but if I click on something, either on purpose or accidently, and I come back I am not where I left off and the timeline is completely different now.
