Modifies prefab.
Presses [Apply].
Unity crashes.
Modifications are gone.
oh god why.
Most annoying thing about Unity ever?
prefabs.
I only use very basic prefabs in my game (and most of them are particle systems/line renderers/etc). The rest is generated via script.
That way I never lose any progress due to corrupted/lost prefabs. I lost an entire fleet of vehicles early on in development when my scene went bung and it took all my prefabs along for the ride.
You guys know about the EditModeScene file, right?
My only complaint is that it’s a little slow sometimes. And Monobehavior for mac takes up way to much process time.
Probably would have been helpful once upon a time, but I prefer my current style, which means I dont have to go looking for temp files if I manage to mangle my scene.
Slow cloth simulation and no real time GI… Light Probes are meh
I make a backup of my whole asset folder every now and then.
The thing about prefabs that I find the most problematic is the lack of nested prefabs.
The thing that bugs me about prefabs is the fact that you can’t break the connection on one variable. For example, if I have a location I want an enemy to defend (which is marked by a transform), I can’t alter it’s movement speed without breaking the defense area. Have to create a separate script on a separate game object which applies the defense location at runtime.
For me it’s when I accidentally hit the wrong hot key like ctrl b instead of v. My kingdom for a yes or no question before starting a build!
That there is no “save progress made in play mode” button. I think no matter how long you use Unity you will keep making that mistake 
I know I do.
Ugh… MonoDevelop is just plain silly on the Mac, nothing should run that slow. I highly suggest TextMate2. It’s open source and integrates nicely with Unity.
ah! That’s what the program is! 
I just turned my Monodevelop into this theme!
Thanks a bunch!
There are a lot of little things that annoy me about Unity, but this may be the biggest. The thing is, it isn’t always practical or feasible to tweak all settings when not in game mode, you often need to adjust how one component works alongside another. Having to write down the changes I make, or take screenshots of my editor windows, only to remake them back in editor mode is a definite productivity killer (and overall downer!)
This. This right here.
Not free, but I recently started usingPlayModePersist and its works really well. Definitely increased my productivity.
Been there. Done that. And I agree!
Gigi
hmmm… Most annoying thing… I’d say the current GUI system…
I love working with Unity, for the most part. As for annoying…I just think UT needs to be more engaged with their community and customers.
32-bit