You often end up with copious amounts of smoke that doesn't get inhaled when smoking with a joint or another device that is continuously burning the plant mater

You often end up with copious amounts of smoke that doesn't get inhaled when smoking with a joint or another device that is continuously burning the plant material, and your lungs are only so efficient at absorbing the vaporized THC in the smoke. You can definitely get a bit of the effects by hanging out with smokers, and you can get high by being in a confined space with them.