I can tell I'm really into a game when I end up ditching the objectives to just screw around. If I'm following the quest arrow I'm probably just in it for the plot or for some completionist urge, but if I really like the game I'll start wandering off the main path to just enjoy the environment and satisfy my own curiosity about things.

I know I like a game when I start it at 5pm and then two seconds later it's 11pm and I tell myself I'll just finish this one quest and then boom it's now 1230.

When I think I've been playing for 1 hour, but it's actually been 12.

This is why I'm not sure I actually like Starfield... that simply isn't happening :/

I start 'solving' the game's puzzles in my dreams, or random mechanics from the game show up in my dreams somehow. When that happens I know a game has its hooks deep into me.

When I can't stop thinking about it when I'm not playing it.

Avoiding main quest line advancements in order to make the game last as long as possible.

After overcoming a challenge, reverting my progress so I can try it another way, and then another.

Getting through real-life tasks as quickly as possible because I want to get back to the game.

Contemplating game characters and their motivations when I'm supposed to be trying to sleep.

The game will be my first thought when waking up, and my last thought before I sleep.

I will be in my own bubble playing the game. Not looking at social media, just focused on the game.

When I've been playing for 5 hours and needed a piss for 3 hours.

The biggest sign is when I stop playing it, I notice that it's night.

When I start making notepad lists of long term goals or shopping lists and such, usually in open world games with lots of tasks where you'd forget on your own what you might be working toward

When I go back to do some part over again to try and do it better, or just do it different.

When I start taking screenshots waaaay too often, that's when I know I'm really engrossed in it.

I do this especially often with EU4, like whenever I'm in a gigantic war, or when I've just taken some land and my borders are looking real sexy

When I'm researching things about the game even when I'm not playing.

Starfield is definitely doing that for me. Before that Distant Worlds 2, X4 Foundations, Elite Dangerous, Skyrim, Space Engineers, Empyrion, GTA V, and Minecraft have all done that.

When I have on the video game music and sound effects. That means I’m totally in it.

Otherwise I’ll have Netflix/Hulu/whatever streaming or music playing.

See, so many of the things below I can think of about games I was addicted to but wasn't really enjoying. Like, if I'm hearing the music while I fall asleep? That's a sign I've been playing it a crap load, but I also can think of many games that sucked me in chasing carrots and kept me up until dawn... but the actual fun parts were fleeting.

Games I actually enjoy have me grinning like a maniac once I start getting into top-tier flow with the actions available, like threading needles in a racing game.

Relevant SMBC:

https://www.smbc-comics.com/comic/happy-2

Around the midpoint of a game, often while still enjoying it, I start asking myself how close to the end I am. Let's Plays are great for this. I can just open a playlist and read episode titles until I'm around the same point I'm actually at. Let's say e.g. 45/67 videos or 2/3. If I rarely do this, maybe even not at all, I'm really into the game.

For context, I mainly play quite linear JRPGs. For other games, I usually just look at howlongtobeat.com and compare it to my playtime.

I don't get tired fast.

A boring game will get me tired.

A great game will keep me in.

Tho sometimes it's a bit more difficult to say. The environment may keep me in, but the gameplay mush me away.

Playing for hours

When I start choosing to play that instead of a multiplayer game with mates. And also when I start recommending it to people. It's all kinda involuntary at this point.

ok, I’ll be the one to say it…

an occasional pants adjustment.

what’s that? no, it’s just dragon age or spongebob at bikini bottom, nothing to see here.