What's the boundary between what's okay to share with your manager vs. what's not? Are some things simply too deep?

• Of course, if your manager is bad, it's not great to share more personal matters. Bad managers don't care about their reports, and it will frustrate them when their reports share deeper issues trying to get them to care.
• However, if your manager is good, I believe the contract is as follows: They are responsible for your performance at work; therefore, they have an obligation to address any issue that affects your performance at work.
• The incentives also align. The better reports are doing, the better the team and the manager do. This is especially true for a senior engineer. If a team's senior engineers are struggling, then the team overall is struggling.
• You can get more signal by asking your teammates who have worked with this manager for a longer time what they think of their manager and what they like about them. If you start seeing themes of empathy and respect among their answers, that's a good signal that it's okay to share these deeper issues.
• These relationships take some time to build (I do think it would be strange to share them in the very first 1:1), but if you work hard to build a good vibe between the two of you, you can make a lot of progress really quickly and be quite comfortable sharing deeper things with one another within a month. You can also expedite this process by requesting more time: The best managers I worked with were always willing to hop onto an extra 1:1 with reports they had who really needed extra support and just had a ton of their minds.

Follow up: How can I ask my own peers about my own manager? (Is it something they/anyone would be comfortable sharing especially if u know your colleagues only for few months/weeks)

Follow up: How can I ask my own peers about my own manager?

This is definitely more sensitive and requires a deeper relationship with your peers before going into it.

One "trick" though is to not ask your peers about your manager and simply talk about your manager naturally instead. From there, your peers might respond by talking about their opinions of the manager. So if you're talking to your coworkers about work, maybe you can bring up something like, "Our manager just put me on project X, but it's been hard figuring out everything about X to ship something there." This opens the door for your coworker to talk about a similar experience they had with your manager (if they have one).

Another angle is to bring this up in the team selection phase (i.e. before you have joined the team) where it makes more sense. Back when I was switching teams at Meta, I asked the current engineers on the team I ended up joining (Instagram Ads) what they thought about the manager. I asked the questions from this video: Questions You Can Ask To Evaluate An Engineering Manager