Board Thread:Off Topic/@comment-198.174.0.11-20130910201652/@comment-24081142-20131024110116

Breakable weapons are a bloody nuisance, you either spend a fortune maintaining them or you weigh yourself down with repair hammers and/or spare weapons. Possibly there could be a chance of dropping your weapon while blocking/being blocked by someone with a much higher skill?

Enchantment could have a chance of failing and wasting the soul, as in Morrowind. Likewise alchemy, there could be a chance of either failing to create the potion or creating a defective version which also harms you.

Illusion - chance to cause a random illusion effect instead of the one you were hoping for

Destruction - misfire and affect yourself instead

Restoration - temporarily disable your own natural regeneration

Conjuration - your summoned creature turns on you

Alteration - temporarily overencumber yourself

Block - you drop your shield/weapon

Sneak - you trip, staggering yourself and alerting everyone nearby

Smithing - instead of improving an item, you either make it worse or completely destroy it

Speech - the person becomes intensely unfriendly - not hostile, but they won't converse with you unless you come back tomorrow

Light/heavy armour - you might trip while running, staggering yourself and damaging your stamina

I'd suggest something like a (25% - your skill level) chance for any of these to happen