Let's look at ten ability obstacles.
1. A character lacks the strength or expertise to perform a physical or mental task.
2. He struggles with forming a plan and seeing it through. Planning may not be one of his strengths or his need to have a plan can keep him from taking action on the fly.
3. He does not have enough or has too much time to think it through. The more a character needs time to process, the more anxious he becomes when under the gun. Does he scatter or can he pull it together?
4. Characters differ in their approach to the problem.
5. His natural approach fails and he must rely on his weak side.
Giving your character a task that requires him to use his weaknesses can be an opportunity to show growth.
6. He tries the opposite approach and it backfires.
Use this when you want a spectacular failure during the time when it appears all is lost. He can then tell his partner: "I told you so."
7. He invests effort in the wrong solution and fails.
During the early part of the story, this tactic is often used. The character thinks he knows what the problem is, who the bad guy is, or where the problem lies. He wastes the first half working toward the wrong goal. At the appropriate turning point, he realizes his mistake and recalculates.
8. He is uncomfortable deciding.
Your character's inability to decide can be his worst nightmare or a silent strength. Perhaps he holds back while everyone else rushes ahead and ends up being the only one left standing. He can be pushed by others into the wrong job, the wrong relationship, or the wrong cause. He can act as sole voice of reason. Others will be irritated with his dithering, but his dithering can result in him being the only one to see clearly. Or it can simply cause passive-aggressiveness that drags out the conflict.
9. His timing can be off. He decides too soon or too late.
His amorous attempts can be too little to late or he can come through at the very last minute and change his love interest's mind. He can choose the wrong girl, then meet the right one. He can decide to join the battle too late and strike out on his own to rectify his mistake. Deciding too late could save him from being collateral damage so he can solve the problem on his own.
10. He just wants the problem gone and takes the wrong action.
This is useful in the early part of the plot where you want things to go wrong for your protagonist. A story problem arises, so he make a snap decision or makes a wrong move. This sets up the conflict for the next act. He must spend the saggy middle cleaning up his mess and choosing a new course of action. This course of action often fails as well and he finds the right path in the final act.
For more about how to craft plots using conflict check out, Story Building Blocks: The Four Layers of conflict available in print and e-book and check out the free tools and information about the series on my website.