Their spam filters are wonky, they have dubious dealings that basically sell your inbox to high-enough bidders, accounts ~magically disappear~ (I've had one do so), more frequent downtime, forwarding is only allowed towards other Microsoft e-mail services (unless this has changed), they keep fucking with the AI (initial Googling suggests most people are unhappy with this), and so forth.but why. what does it do to impede the basic acquisition and reading of emails?
To the "average user", these might be "little things", but it's still pretty clear that GMail or even Yahoo! Mail are superior, more reliable e-mail services.