The word is "perception". You may be doing a great service for your customers, but leaving them with a different perception of what you've done.

I learned this lesson hard way. As a programmer/consultant at a large medical facility I was given an important program to write. It was a critical component of a critical system that was supposed to be operational by a certain date. I worked on it mostly from home. My client didn't see me very often, and his perception was that I was goofing off; procrastinating until last moment. As a result, his anxiety level was high, to put it mildly. In fact, I was doing a GREAT job for him, putting in extra time and even a few extra features.

My bad. I should have made a point of letting him know what I was doing so that he would feel comfortable in knowing what was going on. I could have done this in a number of ways both subtle and not-so-subtle. Subtle: "While I was working on this at home last night, I came up with a few questions." Not-so-subtle: "I know you haven't seen too much of me lately, but that's because I've been working on this project at home. I didn't want you to think I was putting it off".

The point is this: if you're doing a good job for your customers, make sure they know it!

Other interruptions can be controlled. For example, you need a plumber to fix sink and have a friend that wants to see your hydrangeas. Schedule them both for same afternoon, i.e., group things into specific time slots if possible and then plan activities for that time that are not sensitive to interruptions.

Another consideration: don't schedule them for time of day that is your best "thinking" time. For example, I am at my best in morning so, when I have a choice, I avoid scheduling things in morning. That way, interruptions don't disturb me when I'm at my best.

Are kids or spouses walking in and asking you mundane questions that could have waited? Have a signal that means "DO NOT BOTHER ME UNLESS SOMETHING IS BURNING OR BLEEDING". It could be as simple as closing your office door. Or, you could turn on a specific light or lamp that would mean same thing. How about a "Do Not Disturb" door hanger similar to those in a hotel? Make it a strict rule and enforce it: they will get idea. Eventually.

We have just scratched surface, but this beast can be tamed with a little thought and creativity.