Some of it is elegantly handling failure on the UX side, so if there is a bottleneck it doesn't feel so bad to the user.
Some of it is building redundancy: using fallback relays, like nostr:nprofile1qqs06gywary09qmcp2249ztwfq3ue8wxhl2yyp3c39thzp55plvj0sgprdmhxue69uhhg6r9vehhyetnwshxummnw3erztnrdakj74c23x6 has been doing, is one way.