I've seen my dad yell (literally) at more than one telemarketer. His voice can be very intimidating at times; usually once he does this, they don't call back. He hasn't gotten in trouble yet.

BTW, he usually doesn't resort to yelling until politely asking them to stop hasn't worked 5 or 6 times...

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999