ATC
 

GOD forbid anything happen during diversion, they can state d reason u diverted on ur behalf.

Well, you did file a flightplan!

Airports make money from the slots and passenger/landing fees...and now a gate is open that the airport could have made $$$ with!

Diverting is sooo inconsiderate and causes increased carbon offsets, lost airport revenue, jobs, baggage fees, acne, and teenage pregnancy.

I always ask for one simple reason-

If it is a minor tech problem I/we are prepared if the situation gets worse. Not only that, the next sectors handling the flight have a heads up that something is not quite right, therefore can manage their work load and won't be caught in surprise if things go bad.

055166K:
I've actually come across this once quite recently when there was a lot of fog around the London area. Nothing was landing at the smaller fields and diversions to the rest were starting to be refused, so one filed to the Big Field, asked for the weather for the smaller one and if anything had landed. The weather had slightly improved and a couple of jets had landed, so diversion request made with the reason "that's where we really want to go"! At least they were honest.

Usually a plane flies from A to B ... if there is suddenly someone requesting a divert I must consider this as "not normal" and therefore ask for the reason.

There could be something I can help you with and although I'd expect that in that case you'd ask for it perhaps the less-than-glowing reputation (false, of course ;) ) of us spanish controllers has made you hesitant to do so.

Another possibility to consider is that your plane has been hijacked (although I haven't seen a single one in my career) and you can't change your squawk so I'll have to ask... in this case evasive responses have as a consecuence that we would have to notify our supervisor... and if we weren't practically bankrupt you could have to jets at your side just because you didn't want to mention your passenger needed a toilet break. :p

In any case "for operational reasons" is fine with me but as mentioned on other posts that doesn't ensure a parking place at your new destination.

Usually its ATC thats telling me that I am diverting for operational reasons.

In the U.S., became a requirement some years ago that we ask why any IFR aircraft changes destination if reason wasn't obvious. "Passenger comfort" works as good as any. We (local ATC) didn't care. Sometimes people in HQ do for various reasons.

V4f-retired.

It became a requirement in the US right after 9/11. Read into that what you will. It now gets forwarded thru the DEN (Domestic Events Network) that EVERYONE monitors.