Yeah and don't take a walk on the sidewalk ever either, you might trip on a 1/4" offset slab...
In my opinion, if the BB feels heavier to you because it's on your back, it probably has alot to do with where the bar is in relation to your center of gravity.
For Example, different squat bars put different emphasis on your body. There are curved squat bars called buffalo bars and cambered bars that feel very different than a
straight bar. There is a piece that snaps on a squat bar called the Manta Ray which I've seen people use in the gym for comfort reasons. That little device changes the dynamic of the squat, people just don't realize it.
Same thing with lunges.
Now, don't quit doing BB squats because you think the bar is going to break your spine in half. The squat by nature is arguably the most technically important and complicated exercise there is, but it is also one with the highest payout in terms of strength, size, and conditioning.