Why WPA-PSK is not secure?

Today most devices are connected to Internet over Wi-Fi, either in enterprise networks, home networks, or public/guest networks. Wi-Fi security has always been a major concern since it's "wirelessly" invisible, and it's hard to tell if you're secured or not. Fortunately, there're some super good Wi-Fi security technologies that help us to secure Wi-Fi, from WPA, to WPA2, and now WPA3.  But unfortunately because they're so good it often gives "false" belief that as long I am using WPA, it's secured. Just like some think that they're protected once they have a firewall, but most of the hacked incidents do have firewall in place. Technologies are just tools and the key about how we use them.

WPA is a security protocol that helps to secure Wi-Fi connections, but WPA itself lacks of