The worst, to me, are the fast putters who are too chicken**** to let their card mates know what their preferences are. If you're gonna run up to the green and putt before I can get clear of the basket area, you've gotta let me know what you want me to do while you're putting.
For example: Sometimes I putt quick - all I want you to do is whatever you're already doing. Don't freeze if you're moving. Don't rush to get out of the way if you're already standing still. I stepped up and started my routine while you were in my line of sight, I don't mind what you're doing. If I forget to inform someone before it happens once, then thats on me and I let them know and I'm clear about the fact that it only bothered me because of something that was my own fault (by putting quick).
By contrast - I've played with so many people, guys who get up and putt fast that literally spend the whole round seething over someone consistently doing something wrong. I was caddying for a friend at an event a few falls ago and another friend was playing with a Michigan pro who I have traveled with and played dozens of tournaments with. Michigan pro was seething all round because the friend I wasn't caddying for would clear basket and then walk all the way out of his line of sight. He wanted my friend to FREEZE as soon as he stepped up to his lie. Nevermind that he kept stepping up to his lie an instant after my friend cleared the disc from the basket.
I eventually got tired of listening to him complain and went and had a laugh with my friend over it, and he stopped doing it.
And of course you also have the reverse - I've played dubs with people who will miss putts and get angry that you chose to stand stock still ("freeze") as soon as they stepped up to their lie if you're caught still in their line of sight.
Whatever it is that you prefer, if you're gonna putt fast you've gotta communicate with your card.