Subway systems in East Asia are mostly pretty good with this in general - I might even say China has a particular advantage cuz the NIMBY types can't really get a great foothold in an authoritarian system...?
One of the things the others seem to be pointing out are some transfers (especially in the older systems) that are unpleasant to experience, sometimes because of crowding resulting from the difficulty of predicting just how exactly the distribution of population in a city is going to change over a long period of time. My little concrete example is the the intersection of Beijing's lines 5 and 10 at huixinxijienankou - the side platforms of line 10 are directly above and perpendicular to the island platform of line 5, so theoretically it should be a pleasant and short transfer from one to the other (only things like cross-platform transfers are significantly shorter). The issue is that around rush hour, both directions of line 10 and the northbound trains for line 5 are quite full. There's already an imbalance just from that (the trains are about the same size, six carriages with four doors on both sides of each), but it's magnified by the fact that the interval between line 10 trains is like 45 seconds at shortest while the interval between line 5 trains is 90-120 seconds, maybe (? it's been a while; I don't really remember). The result is crowding so severe at its peak that station staff have to open up a corridor outside of the fare gates to give enough space for people to get off line 10 trains

after thinking about that for a while, I understood why some newer interchanges would be ridiculously long and inconvenient when I would have thought it would have been easy to construct them together