Awareness is key. I'm probably the opposite of you - which is fine, not a right or wrong thing. I prefer teeing off at 6am and playing 18 holes in 2.5 hours but I don't have that expectation playing a public course on a Saturday afternoon. I think the biggest problem is new players all watching each other hit before starting their routine, seasoned players are already starting their routine while someone is hitting - then they hit right away. Doesn't seem like much but shaving those 30 seconds over 18 holes makes a massive difference.
Totally agree on being ready to play when it's your turn to play. That bugs me BIG time! Someone that literally has like 5 mins of waiting time while the others putt... but then wait until it's their turn to putt and take another several mins analyzing their putt when it's their turn... looking at it from every angle, etc.
Read your putt while the others are putting and then be ready to go when it's your turn.
I'm mostly talking about on a busy weekend just having to be patient and waiting for those in front of you to finish before you can hit your shot. Unless they are being stupid, like I mentioned above, sometimes it's just slow... and I don't really mind just relaxing and enjoying the peaceful time.
I NEVER go golfing if I'm in a hurry for any reason at all. I just don't enjoy golfing if I feel like I have to rush.