I think its safety play. I think we find ways to stand and make balls that work but suffer from attempting shots that give the other guy the table. I am not a runout player by any means but i see the value in bih and can get out with a favorable layout. Pattern play i think is number 2. It helps us plan ahead and know the odds of getting out or playing safe.
I think in the long run, if you have good fundamentals, good potting abilities, and good pattern play, it seems important to be more aggressive. Not all safeties are created equal, and if you're opponent can just jump or kick out of it, you'll wish you had that 50/50 shot you dismissed a second ago. Safety-ing definitely has it's place, and I love a good safety as much as the next guy, but I'd much rather not let the guy back to the table.
When I miss a low percentage shot, it's seems more constructive to examine the chain of events that led me to that low percentage shot. Usually it was poor planning on my part a couple shots ago.
Your win percentage will definitely suffer if you're just trying to get out all the time, and if you don't have the skills to actually back it up. And it's a blurred line between playing super aggressively to improve, and just being a banger.
Also to add to the discussion, I feel like it's failure to try new things and sticking to what's comfortable that is a key part of amateur pool. The other is thinking that every skill stacks neatly on top of another, and the road is straight forward. You don't learn a perfect stroke on day 1, and if your stroke sucks, it won't just magically become perfect with ton's of play.
I think real improvement involves a lot of re-examination of your current skill sets, and how new information effects it. A lot of two steps forward, one step back type stuff. You have to be willing to overhaul or revise stuff (but not pointlessly).
