The hardest pill to swallow is marginal difficulty. Everyone can agree that writing something like a modern full fledged browser is hard. But how hard is it to add a small feature to said browser? Well, the feature in isolation is easy, but the entire browser at that scale is much more complicated than the sum of its parts, so the difficulty comes from incrementing the complexity of the entire browser and not from how hard the feature itself was. Good code design can alleviate this a bit, but not entirely.

That crazy looking chart (except maybe the push timing loop at the bottom) can be implemented with 100 lines of branching if statements. The 20 or so questions it asks probably can be answered by querying ~3 simple APIs (user preferences, channel preferences, thread preferences). The only complicated thing is the push timing loop.

> The only complicated thing is the push timing loop.

... and producing the chart in the first place.