Lag is probably the single most common excuse for mistakes in all internet gaming. From the beginning of the big craze of first person shooters to now, mistakes are chalked up to lag. The expressions change from: "Oh sorry, you didn't get a heal? I lagged real bad!" to "Oh, I had a huge lag spike!" -- even expletive-laced shouts at the lag itself, as if you could personify bad latency. This happens in PUGs, guild runs, and even just friend and family groups.
The question is how often are people actually lagging versus how often is it merely an excuse, because no one else can prove you did not lag. The truth is, it is not always lag -- but sometimes it is. I have went on expletive-laced tirades when I disconnect during a boss fight or see that horrible thing when my entire action bar is lit up with queued spells but I am not moving. However, if you actually make a mistake that is your fault, I am a big proponent of taking credit for and owning it. If you blame lag or someone else every time you make an actual mistake instead of taking ownership of your shortcomings, you never learn from them. Admitting you used an ill-timed spell, moved into the fire, or just got caught up in your rotation and had a lapse of attention allows you to learn and grow from your mistakes (and hopefully never make them again).
Do you ever use lag as an excuse when it was a personal mistake? Is it a common go-to excuse you use often? Or do you believe in admitting your mistakes and trying to get better from them?