Smoked my first cigar, and went WAY too deep into cigars before I knew a single thing about them. Spent about $3k on crappy cigars, or WAY overpriced CC's, then proceeded to think that tap water would be ok to use to humidify. Stopped smoking for a little bit because of crazy hours at work, checked my humidor one weekend to discover the green mold had taken completely over. I lost every last cigar... I didn't smoke nor buy another cigar for a few years after that.
Once I did decide to get back into it, I did nothing but read, read and read some more about everything I possibly could before buying another cigar. During that time, I found this site, and spent hours and hours just reading all the old posts before I even signed up. Read darn near every post going back for a couple of years, heh. I wasn't about to throw away another $3k.
So, to sum that up, I regret using tap water, as well as the prices I paid and the cigars I bought, it was a waste of time, money and tobacco.