While strictly not negative, there are some that could imply you aren't playing your best or are playing the wrong class:
Nemesis - Get five revenge kills. - Means that you've had five people dominating you. However, this doesn't mean all at once, so it's not that negative.
Engineer - Death Metal - Pick up 10,000 waste metal from pieces of destroyed buildings. - To get this, a lot of your buildings (or your teammates/enemies buildings) have to be destroyed. Likely, this is because your sentry or dispenser got destroyed, and you're picking up the pieces for metal to build new ones.
Another class of achievements are ones where, to get them, you have to arguably play your class wrong:
Spy - Die Another Way - Kill a Sniper after your backstab breaks his Razorback. - Why are you backstabbing Snipers that have Razorbacks?
Pyro - Plan B - Kill 10 enemies while you're both underwater. - Pyro + Water = Bad
Heavy - Photostroika - Provide an enemy with a freezecam shot of you taunting while invulnerable. - AKA wasting the rest of the Uber.
Medic - Does It Hurt When I Do This? - Kill 50 Scouts with your syringe gun. - There are going to be some times when you're fighting Scouts, but if you're going out of your way to fight enemies, you're doing it wrong.
Medic - Peer Review - Kill 10 Medics with your bone saw. - See above, but add in the fact that you're not even using a distance weapon for this one. At least they cut back on the number of kills for this one.
Any taunting achievements that aren't taunt kill achievements. There is at least one per class.
The explosive barrels and mines count as traps, and those appear to be the only ones that can be reset consistently. Some of the others are story related and you have to reload to the point before them.
The reset for explosive items can be triggered by having a zone reload. You can accomplish this by going to a save point, changing and outfit, and exiting out. With the explosive things, you sometimes have to have the enemy hurt prior to killing them with the item.
I actually went the route of reloading the area with the boulder and found that to be quicker and more reliable way to get the achievement.
Best Answer
All me and my friends had to do was hop in the Bulldog with the mounted gun and shoot down all the ships. None of them seem to try to escape, so just blast away.