Karl, yes I have some glider time and I've always wanted to get my glider rating but it allways comes down to the two things we all need more of in life;
1. Time
2. Money
Until I get my 4 kids (and 6 horses) off my "Payroll" I won't be adding any "Fun" stuff like that to my debit card.
Before I got my first ride in a glider, I thought it would be like going up in any Cessna and turning off the motor, then slowly gliding back to earth, in about 5-10 minutes. But after we disconnected at about 3,000' we flew for over 45 minutes!
It was great fun, I hope to someday get into it, but there's only so much money in the bank account and I relly need a new main and jib if I'm going to keep racing sailboats.
The one drawback about gliders is, you have to go to an airport, then you need a tow plane (or car, or winch) to get you up there to begin with, so it's not a sport you can do "Alone" any time you have the urge. It becomes a big production every time you want to go fly, with more money spent (and time wasted) sitting around waiting your turn in line for a...wait for it...a tow-job!
And your dad was right aobut the 3 F's, rent it!
The two things I do like about sailing vs. flying is, in 30+ years of sailing, I have yet to spend a dollar on gasoline for my boat. And I can do it -alone- any time I want, with no outside help required...usually. Oh, and I can legaly drink a beer while sailing...in fact I think it's required.
The two sports are very much the same with the physics involved, lift, drag, thrust, gravity, all that stuff works the same on both sailboats and airplanes. I don't know if you have ever seen the book "High Performance Sailing" by Frank Bethwaite, (if not, get it!) but Frank was an Australian Airforce pilot back in WW 2 I think, and then a competition Glider pilot, but also an awsome sailboat racer/designer of their 18' skiffs.
The two sports go hand in hand. If you can do one, you can do the other, given enough time and money of course! And if you want to do both, I suggest you stay single! You can always rent it. And remember, you are NOT paying for the Sex, you are paying for her to LEAVE when you are done!