For such claims as "Best OS", and "Most Elegant OS UI"... I have a few things to say.
1) Having two windows in-focus
Yes! I did it! I had both a text document and Safari both in focus... short-cuts went to the text window (cmd+t brought up a font dialog cmd+v pastes into textedit),... my normal typing went to Safari!
The Safari AND TextEdit windows had focus, but the menu was TextEdit's. (further reading suggests I have changed the short-cuts to ctrl-based, but this failed horribly and I went back to cmd-based)
2) Parallels causing the screen saver to be disrupted, and upon moving the mouse, the unlock screen vanishes and the full-content of parallels is visible! But OS X it's still locked... and various screen glitches occur.
1) OK, I have two text documents open. So I open another! The two are in one space, and I'm in another when I open a third text document. Which also then takes me to the space the other two are in... but the text document I JUST OPENED! opens in the space I WAS JUST IN! UGH!
2) Various other logic-defying actions.
1) In Mac mail type "gggggggggggggggg" then delete some from the start of the line, and you'll leave trails!
2) Then there are tool-tips that don't fully load nor do they full disappear without causing another one (usually from the souce app) to display.
3) *cough*Extremely Excessive*cough* shadows on windows.
1) F2 shortcut to rename doesn't work.
2) Remapping keys is a great exercise in futility! Since each application stills like to act completely stupid. Not how I have expressly told the system to operate via keybindings. Not just a problem with 3rd party software(major), but also Apple's own(moderate).
a) Right-clicking in Mail automagically creates an annoying selection so it makes pasting time consuming. Since remapping paste to CTRL-v DOESN'T WORK and it does END [of page] instead (even though keybindings should have it goto end of line!)
b) Drag and drop and selections in thunderbird? What a pain!
In thunderbird, the menu: message | copy
messes up reassignment of CTRL+c for copy. Mac's Mail works the opposite, copy is fine but can't paste into message with CTRL+v, it does a typical mac End [of content]. Ugh. Just UGH!
3) No 'cut'ting of files. I guess it's too hard to tell the OS to 'virtually' cut a file (then perform a move), and then if it never happens (paste)... nothing happens! This logic would be asking too much?!
4) Double-clicking the titlebar minimizes the window. When does one EVER double click to MAKE *anything* HIDE?
5) Triple-click to select-all-of-a-line? Keep clicking to do the same. Odd.
6) No drag-and-drop reordering of menus!
7) Windows are slow and choppy to move or resize, especially the more there are.
8) UI basically frooze and I was unable to do anything. BUT! The BG still changed (on 1/2 hr timer)! I hard-rebooted after a few minutes of waiting patiently for me to be able to control the UI again (never happened).
9) Try to close textedit and it covers the window with the confirmation dialog so you don't even know if there's anything there... if you should save or not.. unless you cancel and do it all over again and THEN pick your option. Read: The fluid animation might be needlessly pretty... but it's also needlessly wasting my fucking time.
10) I would like to be able to resize a window from all four edges.
11) I think the central menu idea is stupid.
12) Lack of customizability (but it's a Mac, Mac users would never want to customize anything to a reasonable extent) Instead of turning off the stupid time-wasting eye-candy, you get various forms of time-waste-management. You get to choose from Slow Down My System on a 9 to 10 scale, with 9 being Super Slow-mo, and 10 being Steve Job's Suggested Slowness which speaks to your average Mac user.
And finally more tales of spaces to satisfy point 2 I made earlier.
So you have an application open, it's in your dock, it has multiple windows... those windows are now in different spaces (applies to databases for me!).
You forget which one!!! Now your screwed out of a few minutes!
Or you hide this application, and then bring it back, and it goes wildly among spaces!
Clipboard chops off or adds to the last character(s) when switching in/out of Win XP in parallels.
Firefox 2 crashes daily!
If it wasn't for Opera and Parallels(WINXP)... my job would drive me completely crazy. I just think of how incredibly more straight-forward everything is on Windows.
You know you're using a horribly coded OS when 'excessive' (more than 1?) desktop icons cause system latency to increase. Seriously, disable 'Desktop features' (basically disable desktop except the wallpaper) from Tinkertool and it speeds up system responsiveness.
"Vista is the new Mac." - FireXtol