First, comfortable pants.
Comfortable pants are usually sweatpants, but they can also be a pair of old jeans. They inhibit your movement only minimally. They allow you to sit without exposing your butt crack. They feel almost as good as not wearing pants, except nothing feels as good as not wearing pants. However, if you have to wear pants, comfortable ones are the best option.
Comfortable pants will never let you down, especially when you leave the house wearing them because people will think you are a hobo and will give you leftover sandwiches.
Polar bears are awesome.
The second class of pants are stylish pants.
These pants generally have rips, tears, fading, and other signs of wear. These damages are intended to make you look attractive. You may think that these pants will garner you free leftover sandwiches. You are mistaken. Stylish pants often have strange and shiny logos emblazoned directly on the butt pockets so that each rump-cheek glistens with rhinestones and advertising. These pants will, in no particular order: suffocate you, rip in the crotch at any sudden movement, disallow you from running away from pursuers, prove extremely difficult both to insert your body into and to remove from your body, and make bare your butt crack for all the world to see. They will also situate around your pelvic area in a way that will cause your girth to overflow out of them like a waterfall of fat, no matter how skinny you are. If you are not skinny, they will eventually cut off your blood circulation, and you will die.
The third class: trendy (for some reason) pants.
"Trendy" pants are puzzling in that they are invariably hideous and clearly unfit for anything other than stockpiling extra fabric for sewing together a sail in case of abandonment in an ocean. The "invariably hideous" factor is key to trendy pants, because whether they be checkered, tie-dyed, a blinding shade of neon, or these monstrosities, this category of pants causes the wearer shame in future years.
Overalls don't count as pants, and polar bears are still awesome.