AN: Ok for the past while I have been coming up with a list of things that the BAU aren't allowed to do. Most of this is hopefully funny and as the title suggests, I'm aiming for 101 of these. If you have a suggestion feel free to add it. Enjoy.

Special Agent Derek Morgan was bored. The serial killers of the USA had all decided to have time off which was normally a good thing. It meant semi-regular hours at the office, sleeping in his own bed, being able to kick back and have fun however boredom had set in. Paperwork was boring. Listening to Reid was even more boring. Emily refusing to help distract him added to the boredom. So with nothing to do and nothing interesting to distract him, Derek Morgan was bored.

Little known fact, bored Derek Morgan led to immature Derek Morgan. Immature Derek Morgan liked to bother and annoy people just for kicks and there was one thing he did which was his specialty.

It started quietly, barely more than a whisper but Morgan was grinning while he did it and after a few verses, he started getting louder.

"I know a song that'll get on your nerves, get on your nerves, get on your nerves. I know a song that'll get on your nerves and this is how it goes. I know a song that'll get on your nerves, get on your nerves, get on your nerves. I know a song that'll get on your nerves and this is how it goes. I know a son-" Morgan kept singing until he got Emily and Reid's attention. Whilst Reid gave him a confused look and tried to ignore it, Emily was more direct.

"What are you doing?" Emily asked. Morgan had been singing that constantly for the past five minutes and it was starting to bug her.

"Singing." Morgan replied. "I know a song-"

"Why are you singing?" Emily cut in again, trying to keep him distracted so he would stop freaking singing.

"Bored." Morgan answered with a grin. "Why? Is it bugging you?"

"What do you think?" Emily retorted, feeling the pangs of an incoming headache. 'I belong in this team. I fought to be on this team. I can handle this.' She thought to herself. It was still fairly early days for her being part of the BAU team so having Morgan unexpectedly start singing in the bullpen because he was bored was not something she was used to. Yet. A voice in her head added and she squashed that thought. this could not be a regular thing.

"Good." Morgan smirked and started singing again. "I know a song that'll get on your nerves, get on your nerves, get on your nerves. I know a song that'll get on your nerves and this is how it goes. I know a song that'll get on your nerves, get on your nerves, get on your nerves. I know a song that'll get on your nerves and this is how it goes."

"How can you put up with this?" Emily asked Reid who pointed to his ears. Whilst Emily and Morgan had been talking, he had had the foresight to stick ear plugs in his ears. Working with Morgan over the past two years meant the genius was prepared. The three of them were the only people in the bullpen, B team was out on another case, JJ was holed up in her office, Gideon was in his office, Hotch was in a meeting with Strauss (Emily's blood boiled at the mere thought of the woman) so it was just her stuck having to deal with Morgan and his singing.

"I know a song that'll get on your nerves, get on your nerves, get on your nerves. I know a song that'll get on your nerves and this is how it goes." Morgan slid his chair over towards Emily's desk and slid back to his own before she could slap him. All the while he kept singing and occasionally tossing scraps of paper or pen caps at Emily and Reid, trying to gauge a reaction out of them. Reid was in his own little world but flinched when paper or pen lids hit him and he could see Emily was fighting to regain control of her temper.

"I KNOW A SONG THAT'LL GET ON YOUR NERVES, GET ON YOUR NERVES, GET ON YOUR NERVES. I KNOW A SONG THAT'LL GET ON YOUR NERVES AND THIS IS HOW IT GOES. I KNOW A SONG THAT'LL GET ON YOUR NERVES, GET ON YOUR NERVES, GET ON YOUR NERVES. I KNOW A SONG THAT'LL GET ON YOUR NERVES AND THIS IS HOW IT GOES. I KNOW A-" Morgan had was almost yelling at this point and had finally gotten Reid and Gideon's attention, the senior agent chose to ignore them again and Emily finally snapped, getting to her feet and grabbing Morgan by the throat, not tight enough to cut off his breathing but enough for her to make her point.

"I swear to God Morgan, one more word out of you and I'll make it look like an accident!" Emily threatened as Hotch walked into the bullpen and wasn't even fazed at the sight of Emily having Morgan by the throat.

"Prentiss why are you strangling Morgan?" Hotch asked rubbing his temples. He'd just endured an hour of Strauss yelling at him and tearing him a new one and his head was killing him. The last thing he needed was to cover up a murder by one of his team. Again.

"He won't stop with the 'I know a song'. He's been doing it for the past half hour. I'm a patient person Hotch but I have limits." Emily replied, still holding onto Morgan's throat and ignoring his attempts to pull her hand away.

"Alright, Prentiss stop strangling Morgan. Morgan stop with the singing and grow up." Hotch ordered and went up to his office. Emily let go of Morgan's throat and sat back down at her desk to continue her work. Morgan rubbed his throat and grinned at Emily, still feeling a spark of immaturity in him.

"Hey Prentiss," Morgan began but Emily opened her desk drawer and pulled out her (unloaded) gun and aimed it at him.

"Don't even think about it." Emily warned.

Morgan, wisely, stayed quiet for the rest of the day.

Rule 1: Morgan isn't allowed to sing 'I know a song that'll get on your nerves'.