Recently I was lazy and put my slacks on without underwear.
Since then I have not been wearing underwear because this feels much more comfortable.
I always disliked the way my boxers were riding up, especially when wearing jeans.
I recommend everyone to give this a try.

If you are comfortable why not, I tried it once and I'm not comfortable doing it, it's hard to hide your erection, you will be uncomfortable hiding your erection and you will be uneasy, that's one of the purposes of underwear to hide your erection in case you feel you are attracted to a person.