You know you overbuilt your rocket when...

[Rolanvorxariat]

When you accidentally send your craft to jool and orbit all of its moons, then sending a lamder onto vall and a Atmospheric probe into laythe after burning a bit too long on the Duna mission

[LABHOUSE]

If your username is whackjob.

[Alchemist]

When your launcher costs more than its payload

[bwarren109]

...the Gravity Turn becomes a gravity flip, and after a minute of RCS and gimbal, getting back on course, and you still go to the mun, minmus, back to the mun, and then back to Kerbin.

Also, when you take off with your mun lander and get to orbit going the opposite direction of the CM you were trying to rendezvous with, and still having enough delta-v to completely change the inclination of the lander, while still doing all of that.

[Yukon0009]

.....when the thrust provided by the rcs has more energy than a blue hypergiant..

[CalMacDa]

[Guest]

When Jeb exits capsule and steps on the Mun while rocket still standing on launchpad on Kerbin.

[zekes]

http://i.imgur.com/Gy3ZJgV.png

oooh i feel you..... gawd that hurts.

[Alchemist]

When you consider your lander pretty adequate... until you discover that half of the thrust is nullified by exhaust hitting some parts.

[Tabris]

when you realize that it's more efficient to go DOWN than UP

[Columbia]

When you reach orbit with your first stage (with boosters)..

[Alchemist]

When your Minmus rover ends up laying on its belly with the wheels hanging in the air space. On the flats. Because of the curvature.

[dryer_lint]

When your first stage makes it all the way to the destination, and you have to decouple your last set of asparagus boosters before you land

[RocketBlam]

(I'm sure this has been said already, but...)

You arrive at your destination and your first stage still has fuel in it.

[Astrofox]

When you swing by the Mun 10 times before returning back to Kerbin, successfully (yes, this happened to me, I tried to get into orbit without using too much Delta-V).

[magnemoe]

Anything at all you launch from Gilly, on kerbal just managed to kick an small probe into an suborbital trajectory taking it to the other side of the moon, this was bad as it was just build and without fuel.

The kerbal was supposed to add an fuel hose to it so it could be fueled up before sending it to Eve but bumped into it at some speed instead.

Kebals doing eva regulary get up to escape speed from it simply by using the jet pack on surface.

[Astrofox]

Anything at all you launch from Gilly, on kerbal just managed to kick an small probe into an suborbital trajectory taking it to the other side of the moon

GOOOOOOOOOOOOOOOOOOOOOL!

Sorry, I just had to do that.

[Cripion101]

When you get an escape trajectory from Kerbin before leaving the atmosphere

[Astrofox]

When the craft is so large that the Kraken is K.O.'d by just sitting there.

[Brainlord Mesomorph]

(if I made it) Right before I put it on the launchpad.

[match]

...When you deploy your chutes at launch and never really notice.

[MrWalrus123]

When you do an orbital flight, and still have enough fuel to blow up the entirety of the Vatican City

[manni01]

When you are sorting your staging, but it is so messy, that it gets confused and if you staged, your lander's. engines go off, all the parachutes, and half of your solid boosters.

[mythbusters844]

When you reach orbit with your asparagus lifter and later realize that you never even attached fuel lines.

[Astrofox]

When the entirety of the solar system is dwarfed by the craft (it's over 9000 times larger!).