It was scheduled instead of designed
Somebody had to organise something, a date was found, a venue was booked, and the question of what it was for never got asked. The team can tell. Everything else on this list follows from this one.
It papers over something real
A team that is under-resourced, badly led, or in the middle of a reorganisation does not experience a trust exercise as a gesture of care. It experiences it as evidence that nobody is going to address the actual problem.
If there is a known, unaddressed issue, name it at the start of the session or do not run the session. A facilitator who says 'I know everyone is worried about the restructure and this afternoon will not resolve that' buys more goodwill in one sentence than the whole activity will.
It is mandatory fun
Compulsory attendance at something framed as a treat produces a specific kind of resentment that outlasts the day considerably.
Either make it voluntary, or make it clearly work — a working session on a real problem, in work hours, that happens to build the team. Both are honest. Mandatory attendance at an event described as optional fun is not.
And never schedule it outside working hours. Every person with caring responsibilities notices immediately whose convenience the event was designed around.
It rewards one personality type
Fast, loud, improvisational and competitive is one valid register. If every session has that register, you are running a programme for about a third of your people and telling the rest that this is not for them.
Alternate deliberately. A quiz one quarter, a quiet structured working session the next, something physical after that, something written after that.
There was no debrief
The activity generated a shared experience and then everybody went home. Experiences do not convert into changed behaviour on their own. Fifteen minutes of structured questions is the conversion step, and it is the step most commonly cut for time.
Nothing happened afterwards
The debrief produced three commitments, none of which was done. The following quarter, attendance is lower and the room is more cynical, and the organiser concludes the team does not like team building.
Doing one commitment properly is worth more than running four more events.
The most senior person did not participate properly
If the leader opts out, arrives late, takes a call in the middle or performs rather than participates, everyone reads it correctly as a statement about how much this matters.
Conversely, a senior person who goes first on the uncomfortable thing — the failure résumé, the pre-mortem note nobody wants to write — changes what the whole room believes is permitted. This is the highest-leverage ten seconds in any session, and it is free.