>Difficult to please
>Having complicated requirements
>Excessively particular demanding about details
>Very attentive to and concerned about accuracy and detail
>Reflecting a meticulous, sensitive, or demanding attitude
Fastidious is occasionally used as a compliment to describe someone whose attention to detail gives them good organizing abilities, but it is usually used as a disapproving term.
There are several strange sounding synonyms for this word. A few examples are persnickety, fussbudgety, finicky and punctilious.
Example
He was such a fastidious eater that he would eat a sandwich only if his mother first cut off every scrap of crust.
Punctuality is a rare trait in Office, but he was fastidious about it.