Sounds like the lack of boarding manners.
You follow someone down the aisle and then wait while they slowly take off their jacket,rummage around in their carry on,have a chat to their friend about which of their 2 seats each one wants etc.
They seem to be oblivious to the 70 people they're holding up. I take everything I need out before boarding and hold it in my hand,so I am ready to chuck my bag into the overhead locker and sit down quickly.