I find it quite annoying that Bethesda chose to use certain mutually exclusive activities. Two examples thus far:
1) To enter Power Armor, hit E. To exit PA, hold the E to exit the PA. This conflicts with grabbing things, which require that after placing the cursor over the object to be grabbed, you must press and hold E for a second or so. The trouble is, the player doesn't know all of the objects that are grabbable. Or whether an item is grabbable, but he just didn't have the cursor over the correct pixel to execute the maneuver. So while wearing PA, I go to grab something and the next thing I know, I'm exiting the PA. In and out, in and out, all because both functions use the press-E-and-hold mechanic.
2) Tossing grenades requires hitting the Alt key. However, while using a sniper scope zoomed in, the player uses the Alt key to hold his breath (thereby steadying his aim). For one thing, it means that the player can't be zoomed in and while doing that casually lobbing a grenade in that direction. But more frequently it means that during a fire fight where the player tries to steady his aim at the same time as zooming in, there goes a grenade. (Quite annoying when trying to be stealthy with a suppressed sniper rifle. "What was that??" becomes "We're under attack!")
I checked the Controls option and there's no ability to assign different hotkeys to these several functions. That forces me to endure getting the wrong results when choosing those actions should be simple and distinct.