When you see someone you like, you can't really help it. Unfortunately there are a couple of cases where it's just entirely inappropriate to make it known that you fancy them. In case you didn't realize there are taboos here's a short list, you can base your actions on not doing these from there on.
1. Friend's Family
Mate's Mums, sister's, brother's, dads, best leave it out, it's one thing to say you did it, it's another thing to do it. Like, how fucking awkward would it be if you two made a go of it and had a messy break up? Hanging out at your BFFs place suddenly got a verrry unappealing.
2. Your Lecturer
Hilarious to see when someone tries it on with the lecturer at the end of the class. The attraction is in the power and authority they have. Like, we've all been there. But c'mon guys, can you honestly see it ever happening?
Just a bad idea in general. You're stuck with them for hours a day in close proximity, you're gonna end up falling for 'em. Nights out are the worst because you need a drink but your inhibitions are gone out the door too. Don't shit where you eat is a saying for a reason people.
4. Your Boss
Pretty much anyone in a higher position than you. I understand it, power is sexy, they might be a little bit older which is kinda fun but making come to bed eyes at them during your presentation is probably not the best idea. No, wait, it might be a great idea. It can go either way really but it's risky. If you start to tank during it maybe give it a go, just pop a shirt button/your fly.
5. Your Mate
Couple of drinks in and a few laughs then it happens. The sound of glass breaking, time slows a little and you say "hey wait a minute s/he's pretty hot. Aw wait...shit..." Not much you can do at this point. You're fucked. Unless they're secretly in love with you too?
6. Your Sibling's Girlfriend/Boyfriend
Seriously, eyes to yourself. Don't be that shitty person.
7. Your Boyfriend/Girlfriend's Family Member.
It just means that they come from good stock. It's a compliment to them. Also, seriously inappropriate, eyes to yourself again.
8. Someone At A Funeral
You see, weddings are fine because they're happy occasions and everyone's getting drunk and it's just fun. Spying someone across the church at a funeral and thinking "hot damn" is probably pretty inappropriate.
Video: Inappropriate Crushes