What am I looking at?
Instead of looking at season-long averages, this chart shows only the most recent games. This more accurately shows if a team is recently playing well or poorly, and if it's their offense or defense (or both?) that is the reason for their recent play. Good teams will show their 'Goals For' to be higher than their 'Goals Against', and the larger the gap between those lines, the more lopsided the wins (or losses) have been.
When Edmonton was on their winning streak in 2023-24, they were averaging 3 to 4 goals per game on offense, which is good, but their defense was the difference, only giving up 1.5 goals per game for a long stretch (see their chart, on/around their 40th game). In that same season, Toronto went on a winning streak around game 50, and their chart shows that all of that was offense-driven. Also in that same season, Vegas started the season with a winning streak, averaging 4 goals a game but also only allowing under 2 goals per game for the first two weeks of play, so credit both sides for that streak.
All goals are counted, including power plays, short-handed, and empty nets.