There are 438 bridges in Venice. I have crossed every single one.
I'd combine into a single sentence: "...bridges in Venice and I have crossed..."
some poor pencil pusher in a drooping Venice government building probably had the unfortunate task of counting them all. It struck me as odd. I didn’t think that this place would had a total.
Personally, I'd drop this. It doesn't add to the story and only slows it down.
Is that a lot? It felt like it was.
How about "It felt like a lot." or "It felt like a lot, but what would I know?"
She shot daggers
I would definitely reword this. "Shot daggers" is very cliched.
old Italian man
Remove "Italian". He's the only old man in the story so far.
I slipped it back into my pocket and looked around. Their weren't many high places in Venice, I realized. At least not the ones a tourist like me could reach.
I don't know if this is needed. I like the idea of him being bored and pulling out his phone. The bit about not having coverage is a nice touch. I just think that the other parts could be trimmed to make the story tighter.
I chased the slow moving pack down the bridge to some other crummy building.
I think "chased" is the wrong word here. It suggests that he's keen to catch up with them. You could definitely find a stronger word than 'crummy', too. I get that it's his voice but it doesn't really pack a punch (clicheTM).
"mastabatory frills"
Not sure what you mean by this. Do you think means that people enjoy that are of little substance? Did you mean 'thrills' instead?
Some bridges i checked off the bridge-bucket list was during the slightly intoxicated rat-in-the-maze type exploration—my idea.
This sentence is very confusing to me. Do you mean that Jake got drunk and wandered around Venice? It really needs a rewrite. Maybe: "A drunken wander through Venice crossed a few more bridges off my list."
Also, "bridge-bucket list" sounds weird.
Up one and down and up the next and so on
The roller coaster simile is great. I don't like this sentence though. "Up one bridge and down the next" or something like that might work better. (Although, how do you go up one bridge and down a different one? Maybe my suggestion is awful.)
Only stopping at a bridge apex when the wine gave me a stitch in my side.
Unnecessary. Cut it.
We were nothing having fun then.
We were having nothing but fun?
we sipped champagne and necked
Is this set in the 50s?
What did they expect us to do? Puzzles?
Nice. Also, I like puzzles.
Coffee? Three bridges away.
This whole bit is really good.
ver the most bridges