What's the key to successful boat ownership? Be smarter than the boat! I've seen a lot of kooky stuff over the years, and know it can be very enjoyable if you do the proper upkeep and preperation.
Key things to remember, always disconnect your battery when you park your boat, even if it's only for a couple of weeks. You wouldn't believe how many people's day, weekend or whole vacation seem to be ruined by a dead battery, and usually their family gets the brunt of their frustrations. And don't forget to check it before leaving the house, batteries at the lake aren't cheap.
Fill your gas tank before going out in your boat! Gas costs way more at the lake, and once again this often ruins people's fun. You should see people's reactions when they had to pay for 100+ gallons at around $4 a gallon. Also, if you're gonna park your boat for any length of time you really need to use a fuel stabilizer.
Install the plug before launching, and carry a spare. Wait, on the other hand, forget it at home, it makes for great entertainment for us!!
Always set the parking brake!!! I've seen a couple of rides go into the lake, most recently in august. Ever seen a new tahoe with only the hood peeking out of the water? You don't really wanna laugh with the family there in panic, but this guy really pulled a big boner on this one, but luckily it was at the end of their vacation. Tahoe was a total loss, along with a lot of electronics too. I think he was in too much shock to feel like an idiot, but you can usually tell the guys that feel like idiots cause they take it out on everybody around them.