Explorations are where GA4 stops being annoying
Most complaints about GA4 are really complaints about its standard reports, which are broad and shallow by design. The analysis people actually want lives in Explorations, which is a separate interface most users never open.
The four worth knowing
Free form. A pivot table. Rows, columns, values, segments. This is where you build the report the standard interface refuses to give you — landing page by source by conversion rate, for example, which is not available anywhere else.
Funnel exploration. Define steps and see drop-off between them. Crucially it supports open funnels — people who entered at any step — which is the honest version of most real journeys.
Path exploration. What people did next. Genuinely useful for discovering unexpected routes, and worth using backwards: start from the conversion and look at what preceded it.
Segment overlap. Three segments and their intersections. Good for questions like "do our organic visitors and our converters overlap at all".
The constraints nobody mentions
Data retention applies here. If your property is on the default two months, explorations cannot look further back. This is the single most common reason an exploration returns nothing, and the error message does not say so.
Sampling on large data sets. Reported at the top of the exploration, and easy to miss. A sampled result is an estimate.
Cardinality limits. High-cardinality dimensions get bucketed into "(other)", which can swallow a large share of rows without warning.
The one to build first
Free form: landing page as rows, session source/medium as columns, sessions and key events as values, conversion rate as a calculated comparison.
That single table answers most of the questions people open analytics to ask, and it is three minutes of configuration.
Save them
Explorations are per-user by default. Share them with the property so the analysis outlives whoever built it, and so the next person does not rebuild the same table from scratch.