I feel I lost so much value vs maniacal fish with AA

I definitely don't think it's a big mistake, if any at all. Since you have position on them I think it's ok to go around a 100. Go much less than that and you are giving them too good a price. And would you want to go only 80 with AK? (Not that you really need to be balanced at 1/3 typically)

I usually size it to about 100, but I sized up because he was in the hand. Then after he folds I felt awful.

My default sizing, with no consideration of reads, would be $100. I don't think it's a mistake to size up a little here, when BB is supposedly tight and UTG is loose. Good things can happen when BB has a strong hand and / or UTG doesn't want to release.

I don't see the point of going 5x for 1/4 effective stacks with AA. Particularly, you know the tight player probably isn't calling and the fish probably doesn't have that much.

If, when the hand started, you decided you weren't even going to look at your cards, and were just going to make a squeeze play on the raiser and caller, what's the smallest amount you would raise to get them to fold? I think $120 is a decent answer to that question.

So don't raise that much.

So...sometimes we get AA and no one has a hand that's strong enough to call our raise. It happens. Can't be obsessed over the result.

If / when someone has a hand they want to play facing our raise, I don't think the difference between $100 and $120 is going to be all that meaningful when we're starting $500 deep at 1/3. But it may vary with the table dynamic. If we have the read that the initial raise is coming from a nitty opponent, it's reasonable to think he's got a strong hand.

One thing that is different here is the BTN straddle. That can often lead to the players in the blinds limping in with top of range, in order to 3B when someone else raises. When the blinds open for a raise over a BTN straddle, I think the ranges may be somewhat condensed and middling, like 77-JJ, some weaker suited aces, some suited Broadways, etc.

The other thing that's different here is the recognition that V thinks *we're* nitty with our 3B range. If V is flatting with QQ+/AK, and opening 77-JJ and weaker suited aces, that's a range that doesn't love calling off any 3B, but may call if the size is smaller.

I don't know what the correct adjustment would be if the reads are right. Maybe we should size way down to look weak, and hope to induce a light 4B from someone, but light 4B's are so rare at low stakes. Especially if the game isn't wild, I don't think the risk of going multi-way as monkey-in-the-middle is worth using a smaller 3B size, just to get a call from a nitty opponent in the BB.

Echoing some of the responses here.

i) You're not somehow entitled to win a big pot with AA. We've all open raised with AA and everyone folds.

ii) I'd probably go smaller, perhaps a 100. Not sure it makes that much of a difference, and 120 is hardly much of a mistake.

iii) You made 11 times the straddle uncontested. It's hardly a terrible result.

I'd probably make it 100, but 120 can't be too bad.

A nit opened to 5x from EP, I'd expect him to be calling or trying to GII. The fact that he folded could just be bad luck.

You won $50 at 1/3 without having to see a flop. Seems fine.