You reap what you sow.
This statement is one of the truest phrases ever recorded: you reap what you sow. If you sow the seeds to a bad reputation, likewise you will reap the fruit of a poor reputation - if you make an action, you'll receive the consequences of doing so. I always keep this in mind when carrying something out; if I didn't I'd probably be far more impulsive than I am.
Ignorance is bliss.
Ignoring something that you probably shouldn't be involved is one of the most satisfying experiences: you can watch from the sidelines. If there's a large amount of drama going on and you ignore it and just watch it unfold, you'll have a blissful experience. A while ago, I used to attempt to stick my nose into everything. After discovering this delight of a quote, however, it's occurred to me that ignoring something unimportant to you can be really enjoyable!