Inertia
I feel like I could... TAKE ON THE WORLD!!
I did say 'pretty' good but only from my own experience I see very few dodgy emails and my spam box is full of phishing mails. The best defence IMO is to use your head and don't trust emails, any system can be exploited.Google's algorithm fails both ways, both by failing to spot new frauds and by labelling some genuine messages as fraudulent. It is nowhere near as good as signed emails.