STY: enable flake8-bugbear
There are some cases where one of the values of a `zip()` was not used. I removed the `zip()`. If the two sequences for `zip()` have different lengths, this would change the behavior.
nice - does this solve all bugbear errors? If so, do you want to add it as an additional dependency to the flake8 check? https://github.com/pandas-dev/pandas/blob/ced764da36bbc493d3ada854983638a8552d36f6/.pre-commit-config.yaml#L39 > nice - does this solve all bugbear errors? 

There are still plenty of other warnings. It might be possible to enable bugbear but we would need to disable some rules/add ignore statements (especially when covering the test code).
 bugbear could be enabled when the following warnings are ignored: B004, B005, B006, B008, B009, B010, B011, B015.

I feel there is something wrong with this test:
https://github.com/pandas-dev/pandas/pull/40570/files#diff-5974844fa02c9b81f3477198023bd02503bf82da1e3d15df6dfd62cdca48666bR132
but replacing `r` with `l` results in some errors.

I honestly do not understand how `v` is used in this test - is there a weird side effect (or I am blind)?
https://github.com/pandas-dev/pandas/pull/40570/files#diff-64777e769142fd7a85a91ae1809c0485036fb28ebb32cc6cccba9ae83646ac15R959
 @MarcoGorelli I enabled almost all of bugbear's checks. The current way to handle B008 might decrease performance a bit (could either add ignore statements or have module-level variables). I like getting rid of unnecessary zip/enumerates, bug things like requiring unused loop variable to be "_" seem annoying > I like getting rid of unnecessary zip/enumerates, bug things like requiring unused loop variable to be "_" seem annoying

I will separate the removal of unnecessary statements into a new PR later today. Would it make sense to have a new PR that enables only a smaller subset of rules that are less controversial?

Skip:
B005 (strip with multiple characters)
B006 (mutable default values)
B008 (function calls in default values)
B007 (unused loop variables)
B301 (iteritems - false positives)
and the already skipped rules in this PR

Personally, I would like to have B007 since it found unused zips/enumerates and weird tests. B005 would also be great: there is a comment in the function that uses `rstrip(".__call__")` that this function has a lower priority because it causes issues otherwise (speculating: might be because of this `rstrip` call).
 sure happy to have some of these enabled in a non controversial PR

then can follow up enabling others