My biggest and most infuriating gripes are the loss of activities and hotspots in VoiceOver and the glitchy networking which means that one in every ten web page loads simply won't start. I've no doubt there are other issues too, but all I know about them is that I remember seeing them there in El Cap and being relieved when they weren't on Yosemite. Oh yeah, text editing in Safari and the way that web views don't load properly are others; just try opening the App Store to see that one.
It's a shame but Apple's attention to detail just isn't there any more and I sincerely wish they'd stop with this creeping featuritis and get back to doing another Snow Leopard: all stability, no new features, and an earnest commitment to making the experience as smooth and delightful as they possibly can. Of course when iOS is selling ten times (and more) more units this is a faint hope. WWDC is nearly upon us and I shall be very interested to see what OS X--no, sorry, "macOS"--brings to the table.
Just myself, as usual.