Yesterday Warren "Mook" Wilson posted about high-point characters. I figured I'd throw in my own experience with high-point Dungeon Fantasy characters.
One thing I have seen high-point PCs is players love maxima. They aren't satisfied with them, but they want to be at them. Maximum HP. Maximum possible Active Defenses. Maximum possible Energy Reserve. Maximum possible ST. Maximum possible everything that concerns their niche.
If there isn't a maximum, PCs don't really know where to stop. Recommended limits sound nice, but as soon as that recommendation isn't accurate, they've lost any convincing power. "You shouldn't need more than 20 skill" falls down as soon as someone missed by 1 and skill 21 would have made the difference. So then you end up with 22, 24, 30, etc. There really isn't any upper limit to potentially useful skill, so it's tempting to just keep pushing it up.
It's better to set actual upper limits so people can be the strongest, the biggest, the fastest, the most skilled, etc.
As a player, you need to realize that you simply can't make yourself flat-out unable to fail by sheer shallow niche-filling purchases. It's impossible. 18s will fail you in GURPS, no matter how much higher it is. You'll never have done "enough" Deceptive Attack (especially if you don't know how much you won or lost by). You'll never have done "enough" damage. You'll never be impossible to kill barring actual traits that make you so. You have to accept this, get good enough to be where you need to be where your character needs to be for the game, and move on. If you undershot, tweak it up a bit.
Even on 500 points it's tough to do everything. Say, a barbarian with max ST, max HP, Mountain of Meat, Naked Rage, Great Rage, Epic Smash, Weapon Master (Barbarian Weapons), solid HT, maximum resistance to Poison and Disease, Very Fit, etc. etc. - you'll run out of points. Remember you don't need to be the Best X at everything - you don't need to be the high HP barbarian, the high Survival barbarian, the strength-feats barbarian, the combat-monster barbarian, etc. You don't need to know every spell as the wizard, or the knight who out-knights every other knight at every aspect of combat. You can't, so focus - have an idea of what your guy is like and do that. Don't maximize things just to maximize. Have a focus, because you need one.
GURPS is point-buy, so anything you spend on A won't be around for B. So the good news for everyone is that it's hard for you to niche-stomp other people even if you're higher value, unless they wholly duplicate your niche. Even then, if having multiples helps, you still have things to do.
At the same time, it's rare you need to absolutely, totally, completely maximize your niche with no other diversity. Doing so tends to come and bite you more than not being the absolute best the game allows you to be at some other thing. You tend to need to do basic adventuring tasks well enough to get by - climb, swim, sneak, lift, carry, etc. - or you hold the group down.
It's generally better to have some capability in other things - even if it's just a specialty within your template and a little backup in something else (a knight with a side of leading troops, or a barbarian warrior with extra Survival specialties, or a undead-slaying holy warrior with a side of demon-slaying). Don't see a big pile of points as a way to just be extra, extra good at the one thing you do. If the game goes long or the adventures vary up, you'll suffer for this and so will your friends.
Embrace the Challenge
Higher points mean tougher challenges. Embrace that. Don't assume that what was tough at 250 points will be easy at 500 points so just get there and things are easy. Ideally, you'll be able to revel in your improvement sometimes but also face challenges that would have stomped your 250-point you flat.
In other words, accept that things get harder as you get better. It's supposed to be that way. This is also why you can't buy your way into safety - you're facing bigger risks. You might need +5 to resist poison just to keep even against the snakes in this dungeon, but you can't buy +5 and think you're never going to worry about poison again. The game is an arms race, because part of the fun of being an epic hero is faces epic challenges.