If it wasn't obvious from the various classes, patchwork anime settings and high speed car chase rules, I don't quite play D&D as it was initially intended. Or maybe I do, if you think the game was made to be customized by the person running it (which I do, or at least I hope.)
Anyway, I do actually use a lot of the rules included, just not as is. Off the top of my head;
Alignment - I love alignment! Sort of. I like to use it as a vague connection to some absurd cosmic plan that you really don't understand. Its not about having any real semblance of moral clarity or purpose; some magic works better on this guy then it does this one and that's really the only semi-concrete thing going on here.
Really, players can write whatever the hell they want in this box. In the end, it should matter to them, not me.
Encumbrance - Don't abuse my good will and I won't bring it up. I'm looking at you Jill Valentine.
Descending AC - I like Ascending better, but I think most people do nowadays.
Movement Rates - I'm such a terrible person. I just write in Very Slow - Slow - Normal - Fast - Very Fast and use it to estimate stuff in combat. Hell, I even do this at home and I use a battle-mat.
Ability Score Requirements - Nope. You don't get bonuses for them either.
|Bonky Hammers are "Standard" Weapons|
Always Chaotic Evil/Lawful Good Whatever - Pffft nope.
Morale - I love Morale. I use it for a lot of things though; Will a monster run? Will an NPC stick to their guns in an argument? Will your follower betray you while they are being tortured? And so forth.
Specific Weapons And Armor - I use broad classifications instead of specific ones, just so I can justify any number of absurd aesthetic choices.
Treasure Types - I like to think of them as helpful suggestions.
Magic Weapons or Armor with flat bonuses - Generally you'll get a "Strikes/Protects as Magical as well as this other unique thing" because I just like that.
Please note that these aren't slights or commentaries on the rules above or anything else; I just think its genuinely interesting to talk about this kind of thing.