why does mixing psychedelics (acid, shrooms) and weed amplify it so much

when ever ive done shrooms or acid towards the end i always smoke a bit of weed to try get me a bit sleepy and it always just blows up the trip and makes it insane (not in a bad way) but why does it do this? (why 100 word limit whenever i try find info it trys to tell me not to mix 😐