The problem, I've found, is players who are unable to articulate a course of action because they don't have a firm grasp of the rules, and then get bogged down in the action economy minutiae.  I'm not usually the DMs in these games, so I generally have to grit my teeth over it.
		
		
	 
You've never had fun conversations like this?
Player:  "I want cast bless on the myself and my 3 friends here, here, and here."
DM:  "Ok, that's 4 people, you'll need to spend a 2nd level slot for that."
Player: "Oh, wait....I don't have any more 2nd level slots."
DM:  "Well, you can use a 1st level slot, and just bless 3 people."
Player:  <thinks for 10 seconds>
Player:  "Can I use a 3rd level slot instead?  I have those."
DM:  "Sure, if you use a 3rd level slot you can bless 5 people."
Player:  "5 people, OK."  <thinks, looks around at board>
Player:  "I'll bless her, the PC over there".
DM:  "Well, actually, she's out of range.  Needs to be within 30'."
Player:  <thinks for 10 more seconds>
Player:  "Well, I can't bless everyone, so I guess I'll just bless 3 people for a first level slot."
DM:  "Ok, sounds good.  Just remember it's concentration if you get hit.
Player:  "Oh, it's concentration?  That's not good, I have a concentration spell up already.  I'm going to do something else..."