You try and deny your feelings... but there's no use.
...You know you've got it bad.
You can think of a billion reasons why your crush is absolutely amazing.
You're extra, extra careful to look good EVERY morning.
This is you every time you see your office crush.
You've memorized his/her daily work routine. Their coffee break? You got it down. When they go to lunch? Yup. Their time to leave work? Ingrained firmly in your brain. It's called observation, not stalking.
Every time they pass your desk or you run into them unexpectedly, your heart slams very hard against your chest. Thump, thump, thump (it's so loud, can other people tell?!).
When you tell your friends about them:
When they say hi to you in the morning:
When they compliment you/say anything remotely nice:
This is you when your crush tells a joke:
When you see your crush coming to talk to you... (You don't care if it's just to ask a question about the spreadsheet your team is working on.)
When someone interrupts a conversation between you and your crush:
When you know you both will be at the same meeting:
When you see a member of the opposite sex talking to your crush:
You know they better back off.
When it's time to go home and you know you won't see them for the rest of the day:
..but tomorrow is another day!
And you get to see your crush all over again in the morning!