You really need to spend some time thinking about what you are doing and, if you mess something up, you can be in big trouble.

您确实需要花一些时间来考虑您正在做什么，如果您把某些事情搞糟了，就可能会惹来大麻烦。

You'll make nicer code and fewer mistakes, and even if do you mess something up, you'll be closer to a working state that you can go back to.

这样会得到更好的代码，减少错误，即使真的有东西弄乱了，你也更容易让其步入正轨。

Maybe I don't feel that I deserve something so good in my life, and I'm waiting for something - or me - to mess it up.

也许我觉得我的生活中不值得遇到某些如此之好的东西吧，而且我正在等待某事——或者是我——把事情给搞砸。

Because there is something good between us, and I don't want to mess it up.

因为我们之间存在某些美好的一面，我不想搞砸了。

My biggest problem is getting attached when something starts to look good, and being afraid to continue because I might mess it up.

不得不说的是我还没有掌握绘画的精髓，最大的问题在于我做事情有些太谨小慎微了，生怕将好的东西搞糟了。