Mild cognitive impairment is the stage between normal forgetfulness of aging Cognitiva and the development of diagnosed dementia itself. Even though you might have problems with thinking and memory, if they don't interfere with everyday activities and are the result of normal forgetfulness you need not be concerned. Some of the symptoms include forgetting recent events or conversations, trouble doing more than one task at a time, trouble solving problems and taking more time to do a more difficult mental activity.
It seems that ignoring obsessions is an easier task to achieve if obsessions are only mild, however even those with severe or even extreme OCD can eventually use this strategy effectively. As we know and understand, obsessions are completely unwanted and they are very intrusive. Anybody can have unwanted thoughts of course and obviously you do not have to have OCD to experience unwanted thoughts. I'm sure we have all had unwanted thoughts even if these thoughts were along the lines of horrid dreams or nightmares; it is normal.
Most people while experiencing unwanted thoughts in an awakened state would ignore thoughts that are unpleasant; they would pay them no attention. They may recognise them, but quickly dismiss them. Of course, thoughts can come into anybody's mind and sometimes a thought that just pops into one's mind may have an element of pleasure such as suddenly thinking about taking a vacation; a thought out of the blue.