Handling Network Spikes - all kinds

Basically network spikes come in two forms impacting events like a album release or ddos. I am aware that cloudflare can handle both so the site does not crash but I lack some knowledge depth here.

Load balancing - handles spikes and traffic (cloudflare)
Caching - saves cookies so user do not create sessions helping with spikes(cloudflare

Note: wprockets - just causes wordpress sites at least to break, dont get why

I have 2 questions:

Can a admin realistically handle crazy spikes that bring normal workloads to its knees?
When it comes to handling traffic and a website operating as close as possbile to real time w/o the lag, what can I do?