As an example to this. My first character was a Crusader. Decently built but should have been better. After a while I lost faith in the character because ever time I rolled to hit a monster I miss. It grew frustrating that the damn rogue was doing better damage then me because he was lucky with his rolls. Hell I couldn't use my manuvers because I couldn't hit the broad side of a barn. With no IP proofing I got CAPed by a rogue. When I went for a dungeon crashing Zeintarm (sp?) fighter that was a Desert Half-Orc/Half-Minotaur/Half-Ogre the Dm cried foul because I would be auto hitting things and doing an average of 10 damage an auto hit. I IP proofed by optimizing but had to change characters because they felt I was too powerful.
Everyone wants to help a party out (I believe) as well as have a moment to shine.
Zhentarim. Also, the problem here is when you know the game better than the DM himself or/and the other players. You build a character that is good at what he specialize in and etc, which means he doesn't fail at "life". You want the character to not get killed by the next random mook in the streets and play a real "hero" like in fantasy literature, movies, even freaking animes/mangas, etc. The others cry out for cheating because you are competent, and/or doesn't know 90+% of the rules/options you can use for your character which makes up for some shitty games.
Here's another point that makes up for some shitty games; when the DM bans books because "everything outside core is overpowered." Do you know that Wizards, Druids and Clerics are core? So like, yeah. The best thing you can do is teach 'em how the game really works, and that optimization is a part of the game. Puttin your highest roll in INT because you are a Wizard IS optimization. Buying a Headband of Intellect for your Wizard IS freaking optimization. Things should get banned on a case-by-case basis (ex: Candle of Invocation for wish loops etc), not because they are in some "obscure" splatbook, Banning those cuts options to create a real character, compared to Core Only Fighter.
The best thing you can do is teach them how the freaking game works, which can be problematic when you are not charismatic enough or if they do not care to learn more about the game. At that point, there's almost not point even trying and you should only play freeform with them, which is basically what they freaking want probably.
oh wellz sry 4 da rant etc