1.If Shane did something wrong, he got a tap on the nose or a smack on his bottom. But I got a smack on the bottom too and I thought it was OK, particularly as Shane was an extremely smart creature and seemed to understand what we wanted.
最后一句“particularly as Shane was an extremely smart creature and seemed to understand what we wanted.”不太理解，似乎是半句。

2.If something works, you go along with it. You don’t mend what isn’t broken, as they say.

楼上两位理解基本正确。
第一句你的不解似乎是因为多了一个表强调的“particualrly”，强调词其实在语法分析时可以先去掉，这时你就可以看出这是一个由as引导的表原因的从句，此从句中主语Shane带了was和seemed两个谓语动词，两个半句均为主系表（今通称主动补）结构前半以形容词为补足语，后半以不定式为补足语。
第二句现在为西方体育界常用概念。在足球与NBA报道中常见，一般用于“当一个球队一直取胜时，用不着去替换球员（或改变战术）。”类似汉语“锅不漏不补”。意大利一著名足球教练拉涅利人送外号“补锅匠“，可资参考。