Getting frustrated with all the physics props lying around maps, especially "da_morgendorffer".
Grenades will knock the props EVERYWHERE and you constantly get stuck in them, damaged by walking over them, shin high props will block your dive (the computer monitor is one) etc.
All of the smaller props able to be blown around should have player collision disabled IMO. I'd normally just whip up a server plugin and be done with it but I feel that it's something most people would agree with and so should be added to the game itself.