3. "Ing-disease":
This is more to be considered a point 2a, but I think it warrants its own entry. This is a grammatical curiosity most common amongst English speakers from the Scandinavian countries, but it is getting pretty common across the globe. It stems, as far as I know, from a desire to put more action into the written words, culminating with the use of the -ing form instead of the past tense. It usually results in literary characters doing a lot of things simultaneously, usually a lot of impossible things. Use the past tense to describe what people are doing, and only use the -ing form in conjunction with the past tense, if other actions take place at the same time as the "master action" in past tense.
Example:
✔ "Officer Crabtree ran up the stairs to the door. As he reached the top he pulled out his revolver and, checking the magazine was loaded, prepared to kick the door in."
✖ "Running up the stairs to the door, Officer Crabtree checked his revolver for bullets and prepared to kick the door in."
Poor Officer Crabtree can't kick a door in if he's busy running, can he? Maybe he's a par cour master, who knows? It looks silly, nonetheless.
4. Writing for the ∫tage: