and then there are coats and jackets to put away somewhere, handbags and computer cases, even infant seats and musical intruments.
the last passengers to board are often left standing in the aisle with nowhere to put their bags and belongings. If there is no more room to be found,their hand-baggage will have to be off-loaded and put in the hold. It's the law of the jungle. The first to the bins wins.
People become angry and the flight attendants are often caught in the middle. They ask passengers to store small items under the seats, to leave space for others, to free the aisles while others are boarding, but it is becoming more difficult and often more unpleasant. And of course, if crew are stowing passengers' bags, they are not concentrating on their safety duties, checking equipment and passenger's behaviour and needs. This is, after all, a crucial moment before taxiing and take-off with schedules to be respected, too.