I know it's counter-intuitive, but the reason the beer tastes somewhat flat even though it's overcarbed is actually because it's overcarbed. Most of the gas is escaping in the form of foam, and what's left after it has a chance to settle out is usually pretty flat.
Originally Posted by maddad
I am wondering if I should have just pressurized the keg to 25 psi and then shut the valve off?
No, that gas would have been absorbed quickly, and done very little to carbonate the beer. If you want to increase the pressure to speed things up, only leave it at the increased pressure for a couple days.
There are many methods to force carbonate, the most reliable being the set and forget method, which simply means putting the beer on serving pressure and waiting 7-14 days. There are also many different "burst carbing" methods to force carb a little faster. These usually involve increasing the pressure for a SHORT duration, and/or shaking the keg. The video mentioned above from Nothern Brewer is good, and there's also a good thread stickied at the top of this forum-http://www.homebrewtalk.com/f35/keg-force-carbing-methods-illustrated-73328/