Send live traffic through a load balancer and watch how each algorithm spreads it across the pool: round-robin, weighted, least-connections, random, and IP-hash sticky sessions. Take a server down and watch health checks reroute around it.
Try this: on Round Robin, send a burst — every server gets an equal share regardless of how busy it is. Switch to Least Connections and one slow/backed-up server stops getting piled on. Try IP Hash and click Send repeatedly — the same client IP always lands on the same server (that's how sticky sessions work), until you take that server down and it rehashes. Bump a server's weight on Weighted to send it proportionally more.