An easy well to tell if you love what you do everyday is to analyze the average number of times you hit the snooze button in the morning.
There's a massive difference between the waking processes of someone that is excited to get to work and someone that hates what they do everyday.
In most cases, the latter will sluggishly continue to rest, likely let out a painful moan, and slowly begin what will usually be an anti-climactic day filled with passionless work by a cog.
The other workers, the ones that excitedly leap out of bed thanking their bodies for the brief and much needed rest... They're the ones that are most productive everyday, and more importantly, also the ones that are the happiest.
Coincidentally, these are also the people that you never hear say either of these dreadful statements:
"TGIF! I can't wait for the weekend."
"I hate Mondays!"