I'm a landlord, I own a few properties... so far my biggest problem these past few months stems not from tenants, but from Comcast.
Install issues chronologically (past 3 months):
First having to provide a written statement that someone who doesn't live there any more doesn't live there anymore. I'm sorry they owe you $160, but anyone presenting a valid lease and saying they live there now should be enough for you.
Second, even though it's been supposedly corrected for every single tenant I have, they can't seem to understand that apartment 1 is in the front of this house, the one with a "1" on the door, and insist that anyone living there is living in apartment 2, and apartment 4 is apartment 1. I, and my tenants have tried to get this corrected on average once every 6 months as someone moves out or in but any changes they make seem to go nowhere.
Third - comcast install tech called me up as someone wanted a cable run into the far wall and he needed permission. I asked him if he knew he could punch a hole on the wall and go straight to the basement (where all the wires run) and patch in and he said "uh huh... wait... what?" and I said to punch a hole in the wall, and run the cable clockwise till he hit the door where all the cable runs into. He said "clockwise? what?". I told him to go out, make 2 rights. He said "oh, ok". I show up a day later and the idiot put a splitter on the current run, drilled a hole into the left side of a closet, ran the cable through, drilled a hole in the right side of the closet, a hole in the left side of the front door, ran the cable outside, along the doorstep, drilled a hole for the cable to come back into the house, and then left it there as a dangling cable. 2 outside holes and 2 inside holes to run a cable a distance of 8 feet. He could have even just ran it under the carpet and it would have worked.
Some friends of mine live in one of my places. The house has 3 bedrooms and a large living room and 4 cable outlets. The tech came out, claimed everything was hooked up, got a sign-off and left. He hooked 1 of the outlets up, leaving everything else dead, and lied to the person who was there and said the front room was working. A total lie, there was no way that room was working as the cable ran nowhere. I mean, really, it went into the wall and then out into a room where it lay disconnected. Since comcast has a signoff, and these are my friends, I went to investigate, finding they (or someone else) had slashed some of the wiring and taken the splitters. Basically all the old line was useless. So I ended up doing Comcast's job, buying new splitters, and being out of pocket because of their install team.
Service issues have been fairly regular and severe at my house, and I've been outright lied to be several techs who do not have a clue what they're doing. My personal favorite is an old guy who kept telling me that because my wireless router provided DHCP on client side that that was what was messing with the cablemodem in synching up. I told him in a rather nice way that that was complete BS as to the cablemodem, the wireless router was just one IP and if he would kindly get my internet working I would show him the tech article. He claimed then that my IP phone was messing things up, I pointed to the fact that it, also, was behind the router. He then tried to get me to change to a static IP address saying there was a known issue with Windows XP Pro and I asked him which particular KB reference this was that an XP pro machine could somehow interfere with a Motorola Bitsurfer from behind a WRT-54g, because I never read that one. Short of it is, the problem was a comcast digital cable box. It had fried, it was buzzing on the line. 2 hours of dealing with the same dumbass tech, who even suggested my network might be why the digital cable box was not responding to a hardware ping.