I found a big problem with my game, is that I would rush through certain things. Like I had to make the shot before too much time passed by and something would get out of line. When I land, it's taken me a lot of effort to ask myself "does this look right?", and if it doesn't, to get back up. If you're unsure, then lay your cue on that spot, and stand up and check that the shot is lined up, and reset again, until it looks right.
There shouldn't be any part of your routine that you feel you need to rush through.
You can either take your time and make sure everything is correct. Or you can miss the shot and go sit down. Which wastes more time?
I can't tell you how many easy shots I just take for granted, and then end up having to sit down and think about what an idiot I am. Now my pace is super slow, but I'm also a new player, so there's a lot of things I don't know by heart and have to evaluate on a case by case basis. This means that I should be setting and resetting more than I will later on.
Playing this way also feels way more exhausting, but I would rather play an hour where I'm slowly running out, or almost running out, versus 8 hours of just hitting stuff around, waiting for my subconcious mind to become a pro player.
So take your time, walk around the table, get up to see if you're aimed properly, think about where the ball is going,and exactly where you have to hit the ball and fully commit to the shot when you've thought everything out.
If you're so afraid of playing slowly, than play by yourself, but honestly think about what you're doing. Take note of parts of your game that you try and wing through, and learn to be comfortable with them.