userscript that blocks really really annoying js quirks. web devs should really do this crap themselves...

disable_key_events.user.js

// ==UserScript==
// @name        disable key events
// @namespace   eev.ee
// @description Prevents JS on the page from receiving keyup, keydown, or keypress.  Fixes, e.g., Twitter's disabling of shortcuts until the page has loaded.
// @include     https://twitter.com/*
// @version     1
// @grant       none
// @run-at      document-start
// ==/UserScript==

(function() {
    "use strict";
    var blocker = function(event) {
        event.stopImmediatePropagation();
    };
    ['keyup', 'keydown', 'keypress'].map(function(event_type) {
        // Setting useCapture to true ensures the document receives the event
        // first (during the capture phase, when handlers are run from the
        // outside in).  Most event handlers use bubbling, which runs
        // inside-out.  Even if the page did this same thing, this script runs
        // before there's any DOM at all, so we're guaranteed (I hope) to be
        // the first listener, and stopImmediatePropagation will block any
        // other listeners even for the same event on the same element.
        document.addEventListener(event_type, blocker, true);
    });
})();

never_navigate_to_pound_nowhere.user.js

// ==UserScript==
// @name        never navigate to pound nowhere
// @namespace   veekun.com
// @description Prevent jumping to the top of the page when clicking a poorly-made JS link before the JS has loaded.
// @include     *
// @version     1
// @grant       none
// @run-at      document-start
// ==/UserScript==

(function() {
    "use strict";
    // Capture (third argument true) means this will always run first before
    // any other event handler gets a chance to run (and possibly
    // stopPropagation() without preventDefault()).  So links to # will never
    // ever work.  I think I can live with that.
    document.documentElement.addEventListener('click', function(event) {
        var el = event.target;
        // Gotta run up the tree to look for a link, since we might've clicked
        // a child of one
        while (el) {
            if (el.tagName.toLowerCase() === 'a') {
                break;
            }
            el = el.parentNode;
        }
        // If it's a link to #, don't follow it.
        if (el && el.getAttribute('href') === '#') {
            event.preventDefault();
        }
    }, true);
})();