The infamous Weasel clause - To Wheeze or not to Wheeze

[Sean Winfield]

So as a newbie, I must ask this question.   Your feedback is important because when I do my first deal and the many deals after that, I want to do them RIGHT and more importantly ETHICALLY!  I plan to do my due diligence and crunch the numbers before writing up a contract...I plan to do an inspection when the house is under contract...and more importantly, I want to work to solve the seller's real estate problem!  At the same time, I know things can go wrong and deals don't go through at times...so on to my question(s)...

1. What are your thoughts on including the infamous "weasel" clauses in your contracts?  Do you use them or not?  If not, why not? 

2. Do seasoned investors take you seriously if you use them? If not, is there a better way to say that the deal is no longer going to happen*?  (Note: I'm taking your replies for informational purposes only, I would still check with my attorney when writing up the contracts!! :-)  )