❉ Create a new user in Chrome just for use with debugging, ensures no plugins or extensions are adding JS to the page and confusing the issue. Extension code and iframes will show up when you're trying to profile code and get in the way. You're aiming for as close to a totally vanilla browser tab as possible.
❉ Be aware Chrome dev tools add a fair bit of CPU/memory overhead to the page
❉ "Art" of debugging: replicate, isolate, eliminate. Replication is the hardest part. "Works for me" not really an acceptable answer.