Internet is crawling (single-digit Mbps or less) and the user blames "the Wi-Fi", but the Wi-Fi link is measurably healthy: strong RSSI, high negotiated PHY rate, and a 2-3ms ping to the default gateway with zero loss. No local process is consuming bandwidth. Standard Wi-Fi troubleshooting (channel changes, band switching, moving closer to the AP) is wasted effort because the bottleneck is entirely on the WAN side. The failure looks like a LAN problem to the user because that is the only part of the path they can see.

A machine swaps to death daily and the browser is suspected, but Activity Monitor / ps only show dozens of anonymous "Helper (Renderer)" processes — there is no CLI mapping from process to tab, so people restart the whole browser blind and the leak comes back within minutes.

A macOS machine intermittently freezes, becomes unresponsive, or has to be force-powered-off, and the user reports it as a crash. Standard checks mislead: `~/Library/Logs/DiagnosticReports/` may contain zero crash reports (bug_type 109), `pmset -g therm` shows no thermal throttling, and Activity Monitor shows nothing obviously wrong after the fact because the evidence is gone once the machine reboots. Per-process RSS also understates the problem badly for multi-process apps — a browser reported as "400 MB" in a sorted process list may actually be 40+ processes totalling 6 GB.

On macOS, a GUI app that was running in fullscreen appears to still be open after being quit or force-quit: Mission Control keeps showing a tile for it in the Spaces bar at the top, often rendered as a solid black thumbnail with the app's name under it. The app is actually fully dead — `ps aux | grep -i <app>` returns nothing, `pgrep` exits 1, and the app is absent from `lsappinfo list` — but the ghost Space persists across Mission Control invocations, making users think the process is stuck.

When running the app's Docker web container on a non-default port (e.g. 3003 instead of 3000), Spotify OAuth login fails with "Failed to authenticate". Three separate issues compound: 1) CORS blocks the OPTIONS preflight because the new origin isn't in FastAPI's allow_origins list, 2) The .env file overrides docker-compose defaults for SPOTIFY_REDIRECT_URI causing a redirect_uri mismatch during Spotify token exchange (frontend sends port 3003, backend sends port 3000), 3) Missing database columns (users.youtube_channel_id) cause a 500 error after successful token exchange because alembic migrations were incomplete.

Multi-word searches like react hydration returned irrelevant entries because tag/keyword/framework layer scoring over-weighted multi-layer matches for a single term. An entry matching react in both tags and framework got score 55, passing the 40 percent noise threshold against a top score of 115.