Things you've never did in the trilogy

ME1
Never let the Council die.
Never kill the Rachni queen.
Never let Rana live.
Never sidequest before getting everyone.
Never let Wrex shoot anyone.
Never let Ashley shoot anyone.

Edit: I did the math.  I had one session of ME1 were I walked out with a grand total of 17 renegade points.  Say it with me, "Goodie goodie two-shoes!"

ME2
Never bring an alien to the Quarantine zone.
Never ever side with Mornith.
Never let the time run out on the Thresher Maw. I kill that SOB every time.
Never side with anyone in an argument like Jack v Miranda.
Never romance Thane.
Never romance Jacob.
Never let Mordin kill his former student.
Never fail to let Grunt out of his tank.
Never fail to activate and recruit Legion.
Always immediately go the Omega Relay after the crew is abducted.

ME3
Never let the geth or the quarians kill each other off. I always broker peace.
Never lie about the genophage cure.
Never go to Thessia without Javik.
Never do Leviathan without my LI.
And finally, never go Control.

I was in ME "What did you do" thread when I did that.  This was on my Natashina run. You called me the biggest goodie two-shoe Shepard you'd ever met.   I think I had less than that, tbh.  I remember working with the mob boss, I remember bitching at the Council once after Virmire and of course, Rana had to die.  I don't recall any others.

Here's another one:  I never go a session without bitching out the Council after Virmire.  Even my most paragon Shepards aren't in the mood to deal with their attitude.

-Never played MaleShep.
-Never not exploited the ME1 Paragon/Renegade glitch. ^^
-Never went full Paragon in ME2 and 3.
-Never saved anyone on Feros.
-Never went on a mission without Wrex in ME1.
-Never let him die either.
-Never not brought Legion with me on the Migrant Fleet....Aside from that i think i did everything in ME2 at least once...huh.
-Never went on a mission without Javik in ME3.
-Never discouraged the Joker/EDI romance.
-Never sabotaged the genophage.
-Never let the Quarians live, even when i had the option.
-Never chose the red ending.
-Never played Multiplayer.

Was NEVER able to stick to Paragon or Renegade in all decisions and dialogs. Just couldn't resist the chances to play bad cop during moments where my own patience IRL would be gone when trying to play diplomat with annoying politicians.
I NEVER played Multiplayer, I assume this late game its no longer supported and I don't feel like doing my homework to see if that's an incorrect assumption because I simply do not care.
Never gone through a ME3 mission without Vega backing me up with his Fragmentation Grenades and high weapon damage.

When I can kill a shielded foe in 2 bullets because Vega fired two bullets at the same target, I consider that High Damage.

I am referring to certain enemies, anyone can one shot an unarmored, unshielded soldier. But I am referring to the Brutes. I shoot twice with the M96 Mattock, and Vega does the same with a frag Grenade, the Brute falls over dead. You cannot one shot a Brute with the standard load-out even with all the upgrades; might be possible with the weapon mods but I have that glitch and I am not willing to dig around the files and potentially corrupt my game files.

Not a "choice" per se but I never give up a planetary resource/leave a system uncompleted in ME3. Even when the Reapers are alerted I just fly in and out until I grab the last resource(s) to 100% the system. That it counts as trolling the Reapers is just a bonus.

Pro-tip: when you leave a system and come back you pop in at the opposite end (roughly) from where you left. So if you're trying to get a resource close to say 2 o'clock in a system and that's also where the Reapers come from, you typically don't have enough time to fly to the resource, get it (and God help you if you misclick) and fly back out again due to Reaper acceleration. But if you exit the system at 7-8 o'clock and go back in you'll come out at 2 and be that much closer to your target.

True, but why should I go do a mission and come back when I can just zip in and out of the system and troll the Reapers because they can't do shit to stop me?

I think most people do. That's what's advertized anyway. I discovered you don't have to leave to get the resources, it just requires a little bit of "clever use of game mechanics" to borrow a phrase from MP.

I've never played ME2 without an import from ME1. Never used either Genesis program/comic thingie.

How ever the sound they make when they show up on galaxy map does get annoying after a while.  That being said Reaper trolling is very amusing.