The infected that scratch beyond the windows.

[Riddick_2K 174]

Now the infected run towards the player and, if the player is inside a building, they "pose" (and stop) right in front of a window... the one closest to the player... in 80/85% of cases. For the other times, just wait a bit and the infected will get tired of moving and will "pose" like the others.
In these cases it is extremely easy to kill them even with a knife (except for very thick walls or strange windows).
This can be useful for those who are new and do not yet have the right equipment, but it makes the game very, VERY stupid, as well as "easy"... and a bit "unrealistic", in my opinion... but it can be discussed, since this kind of infected does NOT actually exist (luckily :-P), it is not possible to make direct and precise comparisons with what "should actually be"... just a matter of point of view.
However, in my opinion, it would be much nicer and more realistic if:
*) The infected, once they saw the human beyond a window, would rush pissed off to the edge of the wall and try to attack him beyond the window (always with broken glass). Simpler but more "scenic".
*) The infected would continue to agitate and run around the building, making it difficult to kill them even with a gun, ready to attack the human as soon as he exits the building. Maybe even stopping apparently "cataleptic" behind the entrance door or behind an obstacle in its vicinity... at least for a good amount of time. Protected from the shots beyond the windows, but ready to intervene as soon as the human exits the building (as if a protective instinct had remained imprinted in their minds since they were "healthy", in addition to the aggression acquired by the virus towards "healthy" people).

As it works now, it is too easy to escape from the infected (who NEVER kill), run into a house and, from the window, kill them all comfortably and without any risk.

BE CAREFUL not to allow (as still happens - BUG) the infected to go through walls and windows.
Sooner or later, as soon as I have the right video as proof, I will open a ticket in Feedback.