I mean, it's okay.... I feel like I run into inconveniences in MSO every day. Off the top of my head (solutions welcome):

• Absurd startup times for opening documents. Worse if there isn't an instance of the app already open. Part of the blame goes to my company's antivirus software, but Excel and PowerPoint are easily my slowest-starting apps, and Word is the runner-up. All UI animations are also stupidly slow, though I think that was a design choice.
• A pasted graphic goes to the center of the slide in ppt regardless of the current zoom or view. Annoying for making large posters, exacerbated by delayed rendering of lots of graphics.
• Likewise, zooming occurs relative to slide's center, not the current zoomed view or from the mouse pointer.
• No easily accessibly horizontal scroll outside of using a touchpad (i.e., scrollbar only). Tilting the mouse wheel (if I even have access to such a mouse) either doesn't work or only slightly nudges the view. Also makes posters tedious in combination with pasting issue. Something like shift+mousewheel would be nice.
• Dragging a scroll bar does not update the view until you release it.
• Sometimes the amount of space between a bullet point and text in a PPT text box changes when all others are remain the same. Possibly a skill issue related to styles. Still frustrating.
• Dragging objects autoaligns them to seemingly everything except what I want it to. I now run with snapping turned off.
• Pasting charts between documents changes to destination formatting/styling by default.
• Pasting text from external sources keeps formatting by default. Never have I ever wanted to copy a web page's or email's font, color, and size into my own docs. I could have sworn that there were also circumstances where ctrl+alt+v doesn't work properly, but I can't seem to remember/reproduce that at the moment.
• Dates in Excel. It's a meme, but also true.
• Excel seems to have a "root" window (the doc opened first), and it does not play nice with virtual desktops. If you try to open a spreadsheet from Windows Explorer or some other app (e.g. web browser) on VD B while the root window is on VD A, you are forcibly switched to VD A, where the doc actually opens (after a complimentary delay, of course). Then I have to find the freaking window in Task View and move it back to VD B. There is a reason I wasn't adding more windows to VD A to begin with. Incidentally Word and other MSO apps do not have this issue for some reason.
• If one doc window freezes/stops responding, they all do.
• Aligning things in Word
• A few common color palettes are not colorblind-friendly.