Low frequencies are omnidirectional. When they hit walls they come back without losing much energy, so much so that we credit it with full energy.
That return wave can be in phase well enough to reinforce the original wave when the source is close, or a half wavelength distant from the wall.
But at 1/4 wavelength distance the return wave is fully out of phase and you get a cancellation. The original wave headed out from the speaker towards the wall and away from the wall. Having travelled 1/4 wavelength both ways, before rejoining the original, the reflection is half a wavelength delayed ie a cancellation.
A bass cabinet in a corner gets all the bass energy focused into 1/2 the space of same cab set along a wall.
Go outside and lose half your bass power to the catering area out the back. That's pretty dire!
If you look up Allison Effect it will tell you more than you want to know.