htop is an excellent tool. I appreciate his valiant effort to explain what load average is; it's confused Unix users forever. His explanation is more or less right but I think misses a bit of context about the old days of Unix performance.

It used to be in the early 90s that Unix systems were quite frequently I/O bound; disks were slow and typically bottlenecked through one bus and lots of processes wanted disk access all the time. Swapping was also way more common. Load average is more or less a quick count of all processes that are either waiting on CPU or waiting on I/O. Either was likely in an old Unix system, so adding them all up was sensible.

In modern systems your workload is probably very specifically disk bound, or CPU bound, or network bound. It's much better to actually look at all three kinds of load separately. htop is a great tool for doing that! but the summary load average number is not so useful anymore.