The ADA was amended substantially in 2009. See prior discussion here. With the new ADA in place, disability cases will be more about the accommodation process and less about whether a person is disabled. Workplace Prof discusses a case that sheds some light on the accommodation process. An employee seeking accommodation must present his/her concerns to the employer. 
The employer is then required to respond by either providing the accommodation or offering alternatives. This is known as the "interactive process."
Some employees, inspired by some limited knowledge of the law, then argue with the employer and essentially refuse particular accommodations. The employer is not required to provide the requested accommodation. It is only required to provide an accommodation that meets the employee's need. In Gratzi v. Office of Chief Judges, 601 F.3d 674 (7th Cir. 2010), the employee was a court reporter who had an incontinence problem. She needed a nearby bathroom as an accommodation. She needed to get to a restroom on a moment's notice. But, her position was reorganized into a pool position in which she no longer was assigned to a particular worksite. There was no reason to believe this reorganization was motivated by discriminatory intent.
The employer suggested a number of possible accommodations, all of which were rejected by Mr. Gratzi. She insisted on reinstatement to her previous position. Reinstatement to her previous position meant she would be assigned to one particular worksite. The court reporter did not seek her doctor's advice regarding some of these proposed and then rejected accommodations. She simply rejected them outright. The appellate court found in favor of the employer. The plaintiff, did not, said the court, explain why the offered suggestions would not work. She did not explain why these alternatives would not allow her to get to a restroom within five minutes, as she needed.
Some of the alternatives would have required Ms. Gratzi to raise her hand for a break. She argued that this would cause her embarrassment, possible resentment by other court reporters who would have to cover for her, and would disrupt court proceedings. But, as the 7th Circuit said, this was a detriment more to her employer than to the employee. The court felt she did not do enough to reach an accommodation. A few employees have come to see me lately expressing their resentment at the employer's apparent unwillingness to provide the requested accommodation. But, the law does not require the employer to provide you the accommodation you want. It only requires the employer to provide an accommodation that meets your medical needs.
As Workplace Prof points out, the employee's outright rejection of several alternatives made her an unsympathetic plaintiff. Sympathy does count in litigation. That five minutes of feeling good when you tell the manager "no" can cause long term pain and regret. It would serve any employee much better if they articulate some objective reason why an alternative will not work. Even better, check with your doctor before responding to the employer's offer.
Note that the employer in Gratzi was allowed to reorganize in ways that added to the employee's difficulties, so long as the reorganization was done without discriminatory intent.
